chore: Increase mkdocstrings lower bound (for tests in CI)

Author: pawamoy

Diff for: pyproject.toml

@@ -111,6 +111,7 @@ ci = [
     "mkdocs-minify-plugin>=0.8",
     "mkdocs-redirects>=1.2",
     "mkdocs-section-index>=0.3",
+    "mkdocstrings>=0.29",
     # YORE: EOL 3.10: Remove line.
     "tomli>=2.0; python_version < '3.11'",
 ]