ci: fetch imap-devel from ghcr.io

[kesselb]

No description provided.

[st3iny]

🧹

[ChristophWurst]

/backport to stable2.2

[backportbot-nextcloud]

The backport to stable2.2 failed. Please do this backport manually.

# Switch to the target branch and update it
git checkout stable2.2
git pull origin stable2.2

# Create the new backport branch
git checkout -b fix/foo-stable2.2

# Cherry pick the change from the commit sha1 of the change against the default branch
# This might cause conflicts. Resolve them.
git cherry-pick abc123

# Push the cherry pick commit to the remote repository and open a pull request
git push origin fix/foo-stable2.2

More info at https://docs.nextcloud.com/server/latest/developer_manual/getting_started/development_process.html#manual-backport