"check parent branch" check should not block PR against `v2.0`

[thbar]

Taking down notes to document this (ping @ue71603, @TuThoThai, @ptitfred since this has been discussed with you), even if the fix is going to be easy.

The check I introduced in #1022 to avoid end-of-year costly backports is configured to run only for PR targeting either v2.1-wip or v3.0-wip.

NeTEx/.github/workflows/check-parent-branch.yml

Lines 9 to 11 in 24040c1

	on:
	pull_request:
	branches: [v2.1-wip, v3.0-wip]

This is correct, but as seen in PR targeting branch v2.0 at the moment (e.g. #1030), the status check is verified, but doesn't actually run:

This is caused by the way the ruleset is configured.

I'll share & screenshot & modify it, which will unlock the situation while keeping the check on the correct targets.

[thbar]

What I did so far to fix this:

• create a dedicated "parent check" ruleset only for this check (https://github.com/TransmodelEcosystem/NeTEx/settings/rules/18184752), targeting v2.1-wip and v3.0-wip
• removing this check from the "general protection" ruleset (https://github.com/TransmodelEcosystem/NeTEx/settings/rules/16171342), while trying to fix CI check is (I think, to be verified) not enforced for new (v2.0+) branches #1036 at the same time

I'll try to update a branch and see if this goes away as I expect.

[thbar]

A PR targeting v2.0 now does not wait for the "parent up to date check" anymore, see #1030.

I will keep this open though, as a reminder to verify that branches targeting something different than v2.0 should see that check verified, and not allow merge without it.