deps/gha: bump docker/metadata-action from 5.5.1 to 5.6.1

Bumps [docker/metadata-action](https://github.com/docker/metadata-action) from 5.5.1 to 5.6.1.
- [Release notes](https://github.com/docker/metadata-action/releases)
- [Commits](8e5442c4ef...369eb591f4)

---
updated-dependencies:
- dependency-name: docker/metadata-action
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>

.github/workflows/container-build.yml

@@ -89,7 +89,7 @@ jobs:
       # Compute metadata
       - name: Extract metadata
         id: meta
-        uses: docker/metadata-action@8e5442c4ef9f78752691e2d8f8d19755c6f78e81 # v5.5.1
+        uses: docker/metadata-action@369eb591f429131d6889c46b94e711f089e6ca96 # v5.6.1
         with:
           images: bunkerity/${{ inputs.IMAGE }}
       # Build cached image

.github/workflows/linux-build.yml

@@ -140,7 +140,7 @@ jobs:
       - name: Extract metadata
         if: inputs.TEST == true
         id: meta
-        uses: docker/metadata-action@8e5442c4ef9f78752691e2d8f8d19755c6f78e81 # v5.5.1
+        uses: docker/metadata-action@369eb591f429131d6889c46b94e711f089e6ca96 # v5.6.1
         with:
           images: ghcr.io/bunkerity/${{ inputs.LINUX }}-tests:${{ inputs.RELEASE }}
       - name: Build test image

.github/workflows/push-docker.yml

@@ -65,7 +65,7 @@ jobs:
       # Compute metadata
       - name: Extract metadata
         id: meta
-        uses: docker/metadata-action@8e5442c4ef9f78752691e2d8f8d19755c6f78e81 # v5.5.1
+        uses: docker/metadata-action@369eb591f429131d6889c46b94e711f089e6ca96 # v5.6.1
         with:
           images: bunkerity/${{ inputs.IMAGE }}
       # Build and push