ci: ensure correct commit ref is used for PR workflows

Author: MickaelCa

.github/workflows/docker-build.ecr.yml

@@ -33,6 +33,8 @@ jobs:
     steps:
       - name: Checkout
         uses: actions/checkout@v4
+        with:
+          ref: ${{ github.event_name == 'pull_request' && github.event.pull_request.head.sha || github.sha }}
 
       - name: configure aws credentials
         uses: aws-actions/configure-aws-credentials@v4

.github/workflows/docker-build.ghcr.yml

@@ -44,6 +44,8 @@ jobs:
           egress-policy: audit
 
       - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
+        with:
+          ref: ${{ github.event_name == 'pull_request' && github.event.pull_request.head.sha || github.sha }}
 
       - name: Set current timestamp
         id: vars