🐛 Don't sign tag during autoupdate

This is a temporary restriction since during the implementation of
building the autoupdate functionality and the pipeline handling GPG
additionally would be a bit too much at once.

Refs: #8

update-new-version.sh

@@ -63,5 +63,5 @@ git switch main
 git merge --ff-only version-"$new"
 git push origin main
 
-git tag -s v"$new" "Upstream version $new"
+git tag -a v"$new" "Upstream version $new"
 git push --tags origin main