Bump pygments from 2.1.3 to 2.7.4

Bumps [pygments](https://github.com/pygments/pygments) from 2.1.3 to 2.7.4.
- [Release notes](https://github.com/pygments/pygments/releases)
- [Changelog](https://github.com/pygments/pygments/blob/master/CHANGES)
- [Commits](pygments/pygments@2.1.3...2.7.4)

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

dev-requirements.txt

@@ -4,51 +4,104 @@
 #
 #    pip-compile --output-file dev-requirements.txt dev-requirements.in
 #
-
-alabaster==0.7.7          # via sphinx
-babel==2.3.3              # via sphinx
-backports.shutil-get-terminal-size==1.0.0  # via ipython
+alabaster==0.7.7
+    # via sphinx
+babel==2.3.3
+    # via sphinx
+backports.shutil-get-terminal-size==1.0.0
+    # via ipython
 check-manifest==0.31
-click==6.6                # via pip-tools
+    # via -r dev-requirements.in
+click==6.6
+    # via pip-tools
 coverage==4.0.3
-decorator==4.0.9          # via ipython, traitlets
+    # via -r dev-requirements.in
+decorator==4.0.9
+    # via
+    #   ipython
+    #   traitlets
 detox==0.10.0
-docutils==0.12            # via sphinx
-eventlet==0.18.4          # via detox
-first==2.0.1              # via pip-tools
+    # via -r dev-requirements.in
+docutils==0.12
+    # via sphinx
+eventlet==0.18.4
+    # via detox
+first==2.0.1
+    # via pip-tools
 fmap==0.1
-greenlet==0.4.9           # via eventlet
-imagesize==0.7.0          # via sphinx
+    # via -r dev-requirements.in
+greenlet==0.4.9
+    # via eventlet
+imagesize==0.7.0
+    # via sphinx
 ipdb==0.9.3
+    # via -r dev-requirements.in
 ipdbplugin==1.4.5
-ipython-genutils==0.1.0   # via traitlets
+    # via -r dev-requirements.in
+ipython-genutils==0.1.0
+    # via traitlets
 ipython==4.2.0
-Jinja2==2.8               # via sphinx
+    # via
+    #   -r dev-requirements.in
+    #   ipdb
+    #   ipdbplugin
+jinja2==2.8
+    # via sphinx
 lxml==3.6.0
-MarkupSafe==0.23          # via jinja2
+    # via -r dev-requirements.in
+markupsafe==0.23
+    # via jinja2
 nose==1.3.7
-pathlib2==2.1.0           # via pickleshare
-pexpect==4.0.1            # via ipython
-pickleshare==0.7.2        # via ipython
+    # via
+    #   -r dev-requirements.in
+    #   ipdbplugin
+pexpect==4.0.1
+    # via ipython
+pickleshare==0.7.2
+    # via ipython
 pip-tools==1.6.1
-pkginfo==1.2.1            # via twine
-pluggy==0.3.1             # via tox
-ptyprocess==0.5.1         # via pexpect
-py==1.4.31                # via detox, tox
-Pygments==2.1.3           # via sphinx
-pytz==2016.3              # via babel
-requests-toolbelt==0.6.0  # via twine
-requests==2.9.1           # via requests-toolbelt, twine
-simplegeneric==0.8.1      # via ipython
-six==1.10.0               # via fmap, pathlib2, pip-tools, sphinx, xunitmerge
-snowballstemmer==1.2.1    # via sphinx
-Sphinx==1.4.1
+    # via -r dev-requirements.in
+pkginfo==1.2.1
+    # via twine
+pluggy==0.3.1
+    # via tox
+ptyprocess==0.5.1
+    # via pexpect
+py==1.4.31
+    # via
+    #   detox
+    #   tox
+pygments==2.7.4
+    # via sphinx
+pytz==2016.3
+    # via babel
+requests-toolbelt==0.6.0
+    # via twine
+requests==2.9.1
+    # via
+    #   requests-toolbelt
+    #   twine
+simplegeneric==0.8.1
+    # via ipython
+six==1.10.0
+    # via
+    #   fmap
+    #   pip-tools
+    #   sphinx
+    #   xunitmerge
+snowballstemmer==1.2.1
+    # via sphinx
+sphinx==1.4.1
+    # via -r dev-requirements.in
 tox==2.3.1
-traitlets==4.2.1          # via ipython
+    # via
+    #   -r dev-requirements.in
+    #   detox
+traitlets==4.2.1
+    # via ipython
 twine==1.6.5
-virtualenv==15.0.1        # via tox
+    # via -r dev-requirements.in
+virtualenv==15.0.1
+    # via tox
 xunitmerge==1.0.4
-
-# The following packages are commented out because they are
-# considered to be unsafe in a requirements file:
-# setuptools                # via ipdb, ipython, twine
+    # via -r dev-requirements.in