upgrade Sphinx to 8.2.0 release

[jmckenna]

No description provided.

[github-actions]

The backport to branch-8-4 failed:

The process '/usr/bin/git' failed with exit code 1

stderr

To https://github.com/MapServer/MapServer-documentation.git
 ! [remote rejected]   backport-1011-to-branch-8-4 -> backport-1011-to-branch-8-4 (refusing to allow a GitHub App to create or update workflow `.github/workflows/build.yml` without `workflows` permission)
error: failed to push some refs to 'https://github.com/MapServer/MapServer-documentation.git'

To backport manually, run these commands in your terminal:

# Fetch latest updates from GitHub
git fetch
# Create a new working tree
git worktree add .worktrees/backport-branch-8-4 branch-8-4
# Navigate to the new working tree
cd .worktrees/backport-branch-8-4
# Create a new branch
git switch --create backport-1011-to-branch-8-4
# Cherry-pick the merged commit of this pull request and resolve the conflicts
git cherry-pick 65320fa3cfb9fc90e7f3478861ded83317d4d3c9,4cdbb668c554e95a544d6de27cad605aeff95f84,4d079154234952d960233c4e3af818f412ec3f3f
# Push it to GitHub
git push --set-upstream origin backport-1011-to-branch-8-4
# Go back to the original working tree
cd ../..
# Delete the working tree
git worktree remove .worktrees/backport-branch-8-4

Then, create a pull request where the base branch is branch-8-4 and the compare/head branch is backport-1011-to-branch-8-4.