Check and update branch protection rules

[vikas-agarwal76]

Our current SSF score on branch protection is 5/10.

Check if we can add more rules to improve the score.

[MatteoFari]

I think we could update the ruleset on develop:

1. Require 2 approvals (not 1).
2. Turn on Dismiss stale approvals when new commits are pushed.
3. Turn on Require approval of the most recent push.
4. Make rules apply to admins too, so there's no bypass.

[vikas-agarwal76]

Earlier we had 2 approvers required, changed back to 1 as it was causing delays in PR approvals, especially if the PR was created by a maintainer, as the are only 3 maintainers.
Points 2 and 3 seems reasonable.
In some cases admins require bypass to merge PRs. This can be looked at and only absolutely necessary bypass may be allowed.

[degenaro]

re 1: I think 1 approver for the time being, since we have only 3 maintainers. We should start asking some recent & frequent contributors to become members and reviewers. We should coordinate additional reviewer(s) with the 2 approvals rule.
re 2 & 3: Agreed these seem reasonable.
re 4: I cannot think of any time where admin needed to bypass rules in this project.

[vikas-agarwal76]

@butler54 Please provide your views especially on point4. admin bypass.