build: update e2e workflow

- Update actions to their latest versions.
- Use SHA to (potentially) allow enabling Dependabot.

Signed-off-by: Hidde Beydals <hidde@hhh.computer>

.github/workflows/nightly.yml

@@ -14,16 +14,17 @@ jobs:
   build:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v3
+      - name: Checkout
+        uses: actions/checkout@24cb9080177205b6e8c946b17badbe402adc938f # v3.4.0
       - name: Setup QEMU
-        uses: docker/setup-qemu-action@v2
+        uses: docker/setup-qemu-action@e81a89b1732b9c48d79cd809d8d81d79c4647a18 # v2.1.0
       - name: Setup Docker Buildx
         id: buildx
-        uses: docker/setup-buildx-action@v2
+        uses: docker/setup-buildx-action@4b4e9c3e2d4531116a6f8ba8e71fc6e2cb6e6c8c # v2.5.0
         with:
           buildkitd-flags: "--debug"
       - name: Build multi-arch container image
-        uses: docker/build-push-action@v4
+        uses: docker/build-push-action@3b5e8027fcad23fda98b2e3ac259d8d67585f671 # v4.0.0
         with:
           push: false
           builder: ${{ steps.buildx.outputs.name }}