Add missing step for changed files

Author: SleeplessByte

.github/workflows/pr.ci.js.yml

@@ -12,6 +12,18 @@ jobs:
     steps:
       - name: Checkout PR
         uses: actions/checkout@692973e3d937129bcbf40652eb9f2f61becf3332
+        with:
+          fetch-depth: ${{ github.event_name == 'pull_request' && 2 || 0 }}
+
+      - name: Get changed files
+        id: changed-files
+        run: |
+          if ${{ github.event_name == 'pull_request' }}; then
+              echo "changed_files=$(git diff --name-only --diff-filter=ACM -r HEAD^1 HEAD | xargs)" >> $GITHUB_OUTPUT
+          else
+              echo "changed_files=$(git diff --name-only --diff-filter=ACM ${{ github.event.before }} ${{ github.event.after }} | xargs)" >> $GITHUB_OUTPUT
+          fi
+
       - name: Enable corepack to fix https://github.com/actions/setup-node/pull/901
         run: corepack enable pnpm
 
@@ -37,6 +49,18 @@ jobs:
     steps:
       - name: Checkout PR
         uses: actions/checkout@692973e3d937129bcbf40652eb9f2f61becf3332
+        with:
+          fetch-depth: ${{ github.event_name == 'pull_request' && 2 || 0 }}
+
+      - name: Get changed files
+        id: changed-files
+        run: |
+          if ${{ github.event_name == 'pull_request' }}; then
+              echo "changed_files=$(git diff --name-only --diff-filter=ACM -r HEAD^1 HEAD | xargs)" >> $GITHUB_OUTPUT
+          else
+              echo "changed_files=$(git diff --name-only --diff-filter=ACM ${{ github.event.before }} ${{ github.event.after }} | xargs)" >> $GITHUB_OUTPUT
+          fi
+
       - name: Enable corepack to fix https://github.com/actions/setup-node/pull/901
         run: corepack enable pnpm