Bump certifi from 2023.5.7 to 2023.7.22 in /docs (#979)

Bumps [certifi](https://github.com/certifi/python-certifi) from 2023.5.7 to 2023.7.22.
- [Commits](certifi/python-certifi@2023.05.07...2023.07.22)

---
updated-dependencies:
- dependency-name: certifi
  dependency-type: indirect
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
Co-authored-by: Ben Hoyt <ben.hoyt@canonical.com>

docs/requirements.txt

@@ -1,26 +1,26 @@
 alabaster==0.7.13
-Babel==2.12.1
+babel==2.12.1
 beautifulsoup4==4.12.2
-certifi==2023.5.7
+certifi==2023.7.22
 charset-normalizer==3.1.0
 docutils==0.18.1
 furo==2023.5.20
 idna==3.4
 imagesize==1.4.1
-Jinja2==3.1.2
+jinja2==3.1.2
 lxd-sphinx-extensions==0.0.7
-MarkupSafe==2.1.2
+markupsafe==2.1.2
 packaging==23.1
-Pygments==2.15.1
-PyYAML==6.0
+pygments==2.15.1
+pyyaml==6.0
 requests==2.31.0
 snowballstemmer==2.2.0
 soupsieve==2.4.1
-Sphinx==6.2.1
+sphinx==6.2.1
 sphinx-basic-ng==1.0.0b1
 sphinx-copybutton==0.5.2
+sphinx-design==0.4.1
 sphinx-tabs==3.4.1
-sphinx_design==0.4.1
 sphinxcontrib-applehelp==1.0.4
 sphinxcontrib-devhelp==1.0.2
 sphinxcontrib-htmlhelp==2.0.1