ci: ensure that all the commits are linted by pre-commit hook

This commit ensures that all the commits are linted by pre-commit hook
in a PR.

Signed-off-by: vprashar2929 <vibhu.sharma2929@gmail.com>

Author: vprashar2929

.github/workflows/pr-checks.yaml

@@ -108,7 +108,7 @@ jobs:
       - name: Checkout source
         uses: actions/checkout@v3
         with:
-          ref: ${{ github.event.pull_request.head.sha }}
+          fetch-depth: 0 # Fetch all the history of PR commits
 
       - name: Setup Python
         uses: actions/setup-python@v3
@@ -121,8 +121,8 @@ jobs:
 
       - name: Run Commitlint
         run: |
-          COMMIT_MSG=$(git log -1 --pretty=%B)
-          echo "$COMMIT_MSG" > .git/COMMIT_EDITMSG
+          # Get all the commits between the base and head refs
+          git log --pretty=%B ${{ github.event.pull_request.base.sha }}..${{ github.event.pull_request.head.sha }} | tee .git/COMMIT_EDITMSG
           pre-commit run commitlint --hook-stage commit-msg --commit-msg-file .git/COMMIT_EDITMSG
 
   build-images: