build(deps): update sphinx requirement from ~=6.2 to ~=7.3 (#683)

Updates the requirements on [sphinx](https://github.com/sphinx-doc/sphinx) to permit the latest version.
- [Release notes](https://github.com/sphinx-doc/sphinx/releases)
- [Changelog](https://github.com/sphinx-doc/sphinx/blob/master/CHANGES.rst)
- [Commits](sphinx-doc/sphinx@v6.2.0...v7.3.7)

---
updated-dependencies:
- dependency-name: sphinx
  dependency-type: direct:production
...

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

pyproject.toml

@@ -61,7 +61,7 @@ dev = [
     "urllib3<2",
 ]
 docs = [
-    "Sphinx~=6.2",
+    "Sphinx~=7.3",
     "boto3~=1.26",
     "cartopy~=0.21",
     "geojson~=3.1.0",