Validate pr title for traceability markers (infra)

[Hook25]

Description

We have a new traceability system for PR titles but we have no way to actually enforce it right now beside manually checking.

This changes that by adding a new GH Action that validates the title to check that it actually ends with a traceability marker. To make them not too invasive and hard on contributors, these markers are case insensitive and optionally enclosed in brackets.

Resolved issues

N/A

Documentation

N/A

Tests

This PR was created with a title that does not contain any marker. The job should fail. Once that happens it will be edited to the correct title and it should pass.

Failure: https://github.com/canonical/checkbox/actions/runs/6223347828/job/16889096967?pr=732
Passing: https://github.com/canonical/checkbox/actions/runs/6223329257/job/16889036066?pr=732

[kissiel]

I wrote a simple test for this and I don't know if this is the result we want.

#!/bin/bash

# Array of test values for PR_TITLE
declare -a PR_TITLES=("infra" "bugfix" "new" "breaking" "my new pr (fix)"
                      "Infra?" "Bugfix?" "New?" "Breaking?"
                      "Some random title" "another INFRA" "BREAKING change"
                      "Bugfix at the end?" "Some more texts after breaking?"
                      "Infra!" "bugfix:" "New." "New stuff I'm adding" "traliling space after fix "
                      "fix foo infra" "change bar bugfix" "update baz new" "modify qux breaking"
                      "fix foo Infra?" "change bar Bugfix?" "update baz New?" "modify qux Breaking?"
                      "fix foo (infra)" "change bar (bugfix)" "update baz (new)" "modify qux (breaking)"
                      "fix foo (Infra)?" "change bar (Bugfix)?" "update baz (New)?" "modify qux (Breaking)?")

# Loop over each PR_TITLE and apply the grep command
for PR_TITLE in "${PR_TITLES[@]}"; do
    if echo "$PR_TITLE" | grep -iP "(infra|bugfix|new|breaking)\)?$"; then
        echo "[MATCH] $PR_TITLE"
    else
        echo "[NO MATCH] $PR_TITLE"
    fi
done

Are we not requiring ()?
Moreso, the typical my new pr (fix) marker wouldn't work.

[Hook25]

I have made the brackets compulsory.

As for (fix) no, it is not in our convention right now, we could map it to bugfix and accept it but I think it would become a bit weird. Afterall a fix may be backward compatible, non backward compatible or relative to infra. I'm more on the side of not accepting (fix) as a valid marker

[kissiel]

Oh, sorry, my mistake. Please ignore my input on "fix", "bugfix" is ok.
I've used "fix" so many times before that it's inprinted in my brain.

Overall +1