feat(ci): Verify base image with cosign before building (#184)

Validate the integrity of base image being built from via cosign before
continuing to build. Ensures we only build from signed images

.github/workflows/build.yml

@@ -49,13 +49,18 @@ jobs:
           - image_name: lazurite
             major_version: 38
     steps:
-      - name: Maximize build space
-        uses: ublue-os/remove-unwanted-software@v6
-
       # Checkout push-to-registry action GitHub repository
       - name: Checkout Push to Registry action
         uses: actions/checkout@v4
 
+      - name: Verify base image
+        uses: EyeCantCU/cosign-action/verify@v0.2.1
+        with:
+          containers: ${{ matrix.image_name }}-main:${{ matrix.major_version }}
+
+      - name: Maximize build space
+        uses: ublue-os/remove-unwanted-software@v6
+
       - name: Matrix Variables
         run: |
             REPO=${{ github.repository }}