Bump diff-cover from 8.0.3 to 9.0.0

Bumps [diff-cover](https://github.com/Bachmann1234/diff-cover) from 8.0.3 to 9.0.0.
- [Release notes](https://github.com/Bachmann1234/diff-cover/releases)
- [Changelog](https://github.com/Bachmann1234/diff_cover/blob/main/CHANGELOG)
- [Commits](Bachmann1234/diff_cover@v8.0.3...v9.0.0)

---
updated-dependencies:
- dependency-name: diff-cover
  dependency-type: direct:development
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <[email protected]>

requirements/dev.txt

@@ -40,7 +40,7 @@ coverage[toml]==6.5.0
     #   pytest-cov
 coveralls==3.3.1
     # via -r requirements/dev.in
-diff-cover==8.0.3
+diff-cover==9.0.0
     # via -r requirements/dev.in
 distlib==0.3.8
     # via virtualenv
@@ -104,6 +104,7 @@ markupsafe==2.1.5
     # via
     #   -r requirements/prod.txt
     #   jinja2
+    #   mkdocs
 mergedeep==1.3.4
     # via mkdocs
 mkdocs==1.5.3
@@ -128,12 +129,15 @@ packaging==24.0
     #   pytest
     #   tox
 pathspec==0.12.1
-    # via black
+    # via
+    #   black
+    #   mkdocs
 pkgutil-resolve-name==1.3.10
     # via jsonschema
 platformdirs==4.2.0
     # via
     #   black
+    #   mkdocs
     #   tox
     #   virtualenv
 pluggy==1.4.0