Artifacthub branch update fails on massive policies updates

[jvanz]

When all the policies are being released at the same time, the CI job that updates the artifacthub branch can fail:

+ git config user.name 'Update artifacthub branch'
+ git config user.email github-actions@github.com
+ git checkout -b main --track origin/main
Previous HEAD position was e24b1bf79 Merge pull request #315 from kubewarden/updatecli_main_policies/cel-policy
Switched to a new branch 'main'
branch 'main' set up to track 'origin/main'.
+ git checkout -b artifacthub --track origin/artifacthub
Switched to a new branch 'artifacthub'
branch 'artifacthub' set up to track 'origin/artifacthub'.
+ git reset HEAD -- .
+ git checkout cel-policy/v1.5.6 -- artifacthub-repo.yml
+ mkdir -p policies/cel-policy
+ mv /home/runner/work/_temp/artifacthub-pkg.yml policies/cel-policy/artifacthub-pkg.yml
+ git checkout cel-policy/v1.5.6 -- policies/cel-policy/README.md
+ git add artifacthub-repo.yml
+ git add policies/cel-policy/artifacthub-pkg.yml
+ git add policies/cel-policy/README.md
++ sed --posix -n 's,^version: \(.*\),\1,p' policies/cel-policy/artifacthub-pkg.yml
+ VERSION=1.5.6
+ git commit -m 'Bump ArtifactHub files for policies/cel-policy, version 1.5.6'
[artifacthub ad27f85ad] Bump ArtifactHub files for policies/cel-policy, version 1.5.6
 1 file changed, 17 insertions(+), 17 deletions(-)
+ for i in {1..5}
+ git pull --ff-only origin artifacthub
From https://github.com/kubewarden/policies
 * branch                artifacthub -> FETCH_HEAD
   4b213b5ce..765be7e7d  artifacthub -> origin/artifacthub
hint: Diverging branches can't be fast-forwarded, you need to either:
hint:
hint: 	git merge --no-ff
hint:
hint: or:
hint:
hint: 	git rebase
hint:
hint: Disable this message with "git config set advice.diverging false"
fatal: Not possible to fast-forward, aborting.
Error: Process completed with exit code 128.

A full example of a failure can be found here, in the fist run of the CI.

As far as I can see, this is caused by the concurrent updates in the branch. Therefore, we need to improve the retry mechanism already in place or find a way to make updates sequential.

Acceptance criteria

• Find the best solution for this issue
• Test a massive policy updates

[flavio]

I think we can use a group, something like that: https://github.com/flavio/podlock/blob/add380a9014d8399ab9ef6944f10c4f195b79977/.github/workflows/chart-release.yml#L16C1-L18C28