Bump sphinx-typlog-theme from 0.7.2 to 0.7.3 in /docs (#107)

Bumps [sphinx-typlog-theme](https://github.com/typlog/sphinx-typlog-theme) from 0.7.2 to 0.7.3.
- [Release notes](https://github.com/typlog/sphinx-typlog-theme/releases)
- [Changelog](https://github.com/typlog/sphinx-typlog-theme/blob/master/docs/changelog.rst)
- [Commits](typlog/sphinx-typlog-theme@v0.7.2...v0.7.3)

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

Author: dependabot-preview[bot]

docs/requirements.txt

@@ -4,7 +4,7 @@
 sphinx==2.1.2
 sphinx_autodoc_typehints==1.6.0
 sphinxcontrib-mermaid==0.3.1
-sphinx-typlog-theme==0.7.2
+sphinx-typlog-theme==0.7.3
 recommonmark==0.5.0
 m2r==0.2.1
 tomlkit==0.5.3