Bump sphinx from 5.3.0 to 7.2.6 in /requirements (#541)

Bumps [sphinx](https://github.com/sphinx-doc/sphinx) from 5.3.0 to 7.2.6.
- [Release notes](https://github.com/sphinx-doc/sphinx/releases)
- [Changelog](https://github.com/sphinx-doc/sphinx/blob/master/CHANGES.rst)
- [Commits](sphinx-doc/sphinx@v5.3.0...v7.2.6)

---
updated-dependencies:
- dependency-name: sphinx
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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

requirements/dev.txt

@@ -117,13 +117,14 @@ requests==2.31.0
     # via sphinx
 snowballstemmer==2.2.0
     # via sphinx
-sphinx==5.3.0
+sphinx==7.2.6
     # via
     #   -r docs.in
     #   pallets-sphinx-themes
     #   sphinx-issues
     #   sphinx-tabs
     #   sphinxcontrib-log-cabinet
+    #   sphinxcontrib-serializinghtml
 sphinx-issues==3.0.1
     # via -r docs.in
 sphinx-tabs==3.4.1
@@ -140,7 +141,7 @@ sphinxcontrib-log-cabinet==1.0.1
     # via -r docs.in
 sphinxcontrib-qthelp==1.0.3
     # via sphinx
-sphinxcontrib-serializinghtml==1.1.5
+sphinxcontrib-serializinghtml==1.1.9
     # via sphinx
 tox==4.11.0
     # via -r dev.in

requirements/docs.txt

@@ -42,13 +42,14 @@ requests==2.31.0
     # via sphinx
 snowballstemmer==2.2.0
     # via sphinx
-sphinx==5.3.0
+sphinx==7.2.6
     # via
     #   -r docs.in
     #   pallets-sphinx-themes
     #   sphinx-issues
     #   sphinx-tabs
     #   sphinxcontrib-log-cabinet
+    #   sphinxcontrib-serializinghtml
 sphinx-issues==3.0.1
     # via -r docs.in
 sphinx-tabs==3.4.1
@@ -65,7 +66,7 @@ sphinxcontrib-log-cabinet==1.0.1
     # via -r docs.in
 sphinxcontrib-qthelp==1.0.3
     # via sphinx
-sphinxcontrib-serializinghtml==1.1.5
+sphinxcontrib-serializinghtml==1.1.9
     # via sphinx
 urllib3==1.26.17
     # via requests