workflows: hash pin Actions (#203)

Signed-off-by: Patrick Linnane <patrick@linnane.io>

.github/workflows/docker-pr.yml

@@ -15,7 +15,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Checkout code
-        uses: actions/checkout@v4
+        uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
         with:
           fetch-tags: true
           fetch-depth: 0
@@ -25,7 +25,7 @@ jobs:
         uses: Homebrew/actions/setup-homebrew@master
 
       - name: Setup Homebrew cellar cache
-        uses: actions/cache@v4
+        uses: actions/cache@5a3ec84eff668545956fd18022155c47e93e2684 # v4.2.3
         with:
           path: |
             /home/linuxbrew/.linuxbrew/Cellar
@@ -47,7 +47,7 @@ jobs:
 
       - name: Docker meta
         id: meta
-        uses: docker/metadata-action@v5
+        uses: docker/metadata-action@902fa8ec7d6ecbf8d84d538b9b233a880e428804 # v5.7.0
         with:
           images: ghcr.io/techarohq/anubis