Remove branch name check on PRs in favour of a check on the title

IMO there is no value in requiring branch names to be in a certain format, and just causes people to have to redo work, like would be done here if not for this change

Author: gps035

.github/workflows/pr-lint.yaml

@@ -1,24 +1,14 @@
 name: PR Quality Check
-on: pull_request
+on:
+  pull_request:
+    types: [opened, synchronize, edited, reopened]
 jobs:
   link-ticket:
     runs-on: ubuntu-latest
     steps:
-      - name: Check ticket name conforms to requirements
-        run: echo ${{ github.event.pull_request.head.ref }} | grep -i -E -q "((apm|niad|amb|flagsapi)-[0-9]+)|(dependabot\/)"
-
-      - name: Grab ticket name
-        if: contains(github.event.pull_request.head.ref, 'apm-') || contains(github.event.pull_request.head.ref, 'APM-') || contains(github.event.pull_request.head.ref, 'niad-') || contains(github.event.pull_request.head.ref, 'NIAD-') || contains(github.event.pull_request.head.ref, 'amb-') || contains(github.event.pull_request.head.ref, 'AMB-')
-        run: echo ::set-env name=TICKET_NAME::$(echo ${{ github.event.pull_request.head.ref }} | tr '[:lower:]' '[:upper:]' | grep -i -o '^\(APM\|NIAD\|AMB\)-[0-9]\+')
+      - name: Check PR title starts with Jira reference
         env:
-          ACTIONS_ALLOW_UNSECURE_COMMANDS: true
-
-      - name: Comment on PR
-        if: contains(github.event.pull_request.head.ref, 'apm-') || contains(github.event.pull_request.head.ref, 'APM-') || contains(github.event.pull_request.head.ref, 'niad-') || contains(github.event.pull_request.head.ref, 'NIAD-') || contains(github.event.pull_request.head.ref, 'amb-') || contains(github.event.pull_request.head.ref, 'AMB-')
-        uses: unsplash/comment-on-pr@master
-        env:
-          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
-        with:
-          msg: |
-            This branch is work on a ticket in the NHS Digital APM JIRA Project. Here's a handy link to the ticket:
-            # [${{ env.TICKET_NAME }}](https://nhsd-jira.digital.nhs.uk/browse/${{ env.TICKET_NAME}})
+          PR_TITLE: ${{ github.event.pull_request.title }}
+        run: |
+          JIRA_REGEX="^(APM|NIAD|AMB|FLAGSAPI)-([[:digit:]]+)"
+          [[ "$PR_TITLE" =~ $JIRA_REGEX ]] && exit 0 || exit 1