Bump urllib3 from 1.26.3 to 1.26.4 in /requirements (#102)

Bumps [urllib3](https://github.com/urllib3/urllib3) from 1.26.3 to 1.26.4.
- [Release notes](https://github.com/urllib3/urllib3/releases)
- [Changelog](https://github.com/urllib3/urllib3/blob/main/CHANGES.rst)
- [Commits](urllib3/urllib3@1.26.3...1.26.4)

Signed-off-by: dependabot[bot] <support@github.com>

Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

requirements/base.txt

@@ -4,80 +4,178 @@
 #
 #    pip-compile --output-file=base.txt base.in
 #
-alabaster==0.7.12         # via sphinx
-appdirs==1.4.4            # via virtualenv
-asttokens==2.0.4          # via flake8-aaa
-babel==2.9.0              # via sphinx
-bandit==1.7.0             # via -r base.in
-bleach==3.3.0             # via readme-renderer
-build==0.2.1              # via check-manifest
-certifi==2020.12.5        # via requests
-cffi==1.14.4              # via cryptography
-chardet==4.0.0            # via requests
-check-manifest==0.46      # via -r base.in
-click==7.1.2              # via pip-tools
-colorama==0.4.4           # via twine
-cryptography==3.4.4       # via secretstorage
-distlib==0.3.1            # via virtualenv
-docutils==0.16            # via -r base.in, readme-renderer, sphinx
-filelock==3.0.12          # via tox, virtualenv
-flake8-aaa==0.11.1        # via -r base.in
-flake8==3.8.4             # via -r base.in
-gitdb==4.0.5              # via gitpython
-gitpython==3.1.13         # via bandit
-idna==2.10                # via requests
-imagesize==1.2.0          # via sphinx
-importlib-metadata==3.4.0  # via build, flake8, keyring, pep517, pluggy, stevedore, tox, twine, virtualenv
-importlib-resources==5.1.0  # via virtualenv
-isort==5.7.0              # via -r base.in
-jeepney==0.6.0            # via keyring, secretstorage
-jinja2==2.11.3            # via sphinx
-keyring==22.0.1           # via twine
-livereload==2.6.3         # via sphinx-autobuild
-markupsafe==1.1.1         # via jinja2
-mccabe==0.6.1             # via flake8
-packaging==20.9           # via bleach, build, sphinx, tox
-pbr==5.5.1                # via stevedore
-pep517==0.9.1             # via build
-pip-tools==5.5.0          # via -r base.in
-pkginfo==1.7.0            # via twine
-pluggy==0.13.1            # via tox
-py==1.10.0                # via tox
-pycodestyle==2.6.0        # via flake8
-pycparser==2.20           # via cffi
-pyflakes==2.2.0           # via flake8
-pygments==2.7.4           # via readme-renderer, sphinx
-pyparsing==2.4.7          # via packaging
-pytz==2021.1              # via babel
-pyyaml==5.4.1             # via -r base.in, bandit
-readme-renderer==28.0     # via twine
-requests-toolbelt==0.9.1  # via twine
-requests==2.25.1          # via requests-toolbelt, sphinx, twine
-rfc3986==1.4.0            # via twine
-secretstorage==3.3.1      # via keyring
-six==1.15.0               # via asttokens, bandit, bleach, livereload, readme-renderer, tox, virtualenv
-smmap==3.0.5              # via gitdb
-snowballstemmer==2.1.0    # via sphinx
-sphinx-autobuild==2020.9.1  # via -r base.in
-sphinx-rtd-theme==0.5.1   # via -r base.in
-sphinx==3.4.3             # via -r base.in, sphinx-autobuild, sphinx-rtd-theme
-sphinxcontrib-applehelp==1.0.2  # via sphinx
-sphinxcontrib-devhelp==1.0.2  # via sphinx
-sphinxcontrib-htmlhelp==1.0.3  # via sphinx
-sphinxcontrib-jsmath==1.0.1  # via sphinx
-sphinxcontrib-qthelp==1.0.3  # via sphinx
-sphinxcontrib-serializinghtml==1.1.4  # via sphinx
-stevedore==3.3.0          # via bandit
-toml==0.10.2              # via build, check-manifest, pep517, tox
-tornado==6.1              # via livereload
-tox==3.21.4               # via -r base.in
-tqdm==4.56.2              # via twine
-twine==3.3.0              # via -r base.in
-typing-extensions==3.7.4.3  # via importlib-metadata
-urllib3==1.26.3           # via requests
-virtualenv==20.4.2        # via tox
-webencodings==0.5.1       # via bleach
-zipp==3.4.0               # via importlib-metadata, importlib-resources, pep517
+alabaster==0.7.12
+    # via sphinx
+appdirs==1.4.4
+    # via virtualenv
+asttokens==2.0.4
+    # via flake8-aaa
+babel==2.9.0
+    # via sphinx
+bandit==1.7.0
+    # via -r base.in
+bleach==3.3.0
+    # via readme-renderer
+build==0.2.1
+    # via check-manifest
+certifi==2020.12.5
+    # via requests
+cffi==1.14.4
+    # via cryptography
+chardet==4.0.0
+    # via requests
+check-manifest==0.46
+    # via -r base.in
+click==7.1.2
+    # via pip-tools
+colorama==0.4.4
+    # via twine
+cryptography==3.4.4
+    # via secretstorage
+distlib==0.3.1
+    # via virtualenv
+docutils==0.16
+    # via
+    #   -r base.in
+    #   readme-renderer
+    #   sphinx
+filelock==3.0.12
+    # via
+    #   tox
+    #   virtualenv
+flake8-aaa==0.11.1
+    # via -r base.in
+flake8==3.8.4
+    # via -r base.in
+gitdb==4.0.5
+    # via gitpython
+gitpython==3.1.13
+    # via bandit
+idna==2.10
+    # via requests
+imagesize==1.2.0
+    # via sphinx
+isort==5.7.0
+    # via -r base.in
+jeepney==0.6.0
+    # via
+    #   keyring
+    #   secretstorage
+jinja2==2.11.3
+    # via sphinx
+keyring==22.0.1
+    # via twine
+livereload==2.6.3
+    # via sphinx-autobuild
+markupsafe==1.1.1
+    # via jinja2
+mccabe==0.6.1
+    # via flake8
+packaging==20.9
+    # via
+    #   bleach
+    #   build
+    #   sphinx
+    #   tox
+pbr==5.5.1
+    # via stevedore
+pep517==0.9.1
+    # via build
+pip-tools==5.5.0
+    # via -r base.in
+pkginfo==1.7.0
+    # via twine
+pluggy==0.13.1
+    # via tox
+py==1.10.0
+    # via tox
+pycodestyle==2.6.0
+    # via flake8
+pycparser==2.20
+    # via cffi
+pyflakes==2.2.0
+    # via flake8
+pygments==2.7.4
+    # via
+    #   readme-renderer
+    #   sphinx
+pyparsing==2.4.7
+    # via packaging
+pytz==2021.1
+    # via babel
+pyyaml==5.4.1
+    # via
+    #   -r base.in
+    #   bandit
+readme-renderer==28.0
+    # via twine
+requests-toolbelt==0.9.1
+    # via twine
+requests==2.25.1
+    # via
+    #   requests-toolbelt
+    #   sphinx
+    #   twine
+rfc3986==1.4.0
+    # via twine
+secretstorage==3.3.1
+    # via keyring
+six==1.15.0
+    # via
+    #   asttokens
+    #   bandit
+    #   bleach
+    #   livereload
+    #   readme-renderer
+    #   tox
+    #   virtualenv
+smmap==3.0.5
+    # via gitdb
+snowballstemmer==2.1.0
+    # via sphinx
+sphinx-autobuild==2020.9.1
+    # via -r base.in
+sphinx-rtd-theme==0.5.1
+    # via -r base.in
+sphinx==3.4.3
+    # via
+    #   -r base.in
+    #   sphinx-autobuild
+    #   sphinx-rtd-theme
+sphinxcontrib-applehelp==1.0.2
+    # via sphinx
+sphinxcontrib-devhelp==1.0.2
+    # via sphinx
+sphinxcontrib-htmlhelp==1.0.3
+    # via sphinx
+sphinxcontrib-jsmath==1.0.1
+    # via sphinx
+sphinxcontrib-qthelp==1.0.3
+    # via sphinx
+sphinxcontrib-serializinghtml==1.1.4
+    # via sphinx
+stevedore==3.3.0
+    # via bandit
+toml==0.10.2
+    # via
+    #   build
+    #   check-manifest
+    #   pep517
+    #   tox
+tornado==6.1
+    # via livereload
+tox==3.21.4
+    # via -r base.in
+tqdm==4.56.2
+    # via twine
+twine==3.3.0
+    # via -r base.in
+urllib3==1.26.4
+    # via requests
+virtualenv==20.4.2
+    # via tox
+webencodings==0.5.1
+    # via bleach
 
 # The following packages are considered to be unsafe in a requirements file:
 # pip