Bump pip-tools from 5.4.0 to 5.5.0

Bumps [pip-tools](https://github.com/jazzband/pip-tools) from 5.4.0 to 5.5.0.
- [Release notes](https://github.com/jazzband/pip-tools/releases)
- [Changelog](https://github.com/jazzband/pip-tools/blob/master/CHANGELOG.md)
- [Commits](jazzband/pip-tools@5.4.0...5.5.0)

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

requirements/dev.txt

@@ -4,23 +4,21 @@
 #
 #    pip-compile --output-file=requirements/dev.txt requirements/dev.in
 #
-atomicwrites==1.4.0       # via pytest
 attrs==20.3.0             # via pytest
 click==7.1.2              # via pip-tools
-colorama==0.4.4           # via pytest
 coverage==5.3.1           # via pytest-cov
 iniconfig==1.1.1          # via pytest
 mock==4.0.3               # via -r requirements/dev.in
 packaging==20.8           # via pytest
-pip-tools==5.4.0          # via -r requirements/dev.in
+pip-tools==5.5.0          # via -r requirements/dev.in
 pluggy==0.13.1            # via pytest
-py==1.10.0                 # via pytest
-pylibmc==1.6.1; platform_system != 'Windows'            # via -r requirements/dev.in
+py==1.10.0                # via pytest
+pylibmc==1.6.1            # via -r requirements/dev.in
 pyparsing==2.4.7          # via packaging
 pytest-cov==2.10.1        # via -r requirements/dev.in
 pytest==6.2.1             # via -r requirements/dev.in, pytest-cov
 python-memcached==1.59    # via -r requirements/dev.in
-six==1.15.0               # via pip-tools, python-memcached
+six==1.15.0               # via python-memcached
 toml==0.10.2              # via pytest
 
 # The following packages are considered to be unsafe in a requirements file: