fix(ci): Add Docker auth step to self-action

Author: GeekMasher

.github/workflows/self-action.yml

@@ -5,6 +5,7 @@ on:
     branches: [ main ]
 
 env:
+  REGISTRY: ghcr.io
   EXTRACTOR_REPOSITORY: advanced-security/codeql-extractor-iac
 
 jobs:
@@ -15,6 +16,13 @@ jobs:
       - name: "Checkout"
         uses: actions/checkout@v4
 
+      - name: Log in to the Container registry
+        uses: docker/login-action@74a5d142397b4f367a81961eba4e8cd7edddf772 # v3.4.0
+        with:
+          registry: ${{ env.REGISTRY }}
+          username: ${{ github.actor }}
+          password: ${{ secrets.GITHUB_TOKEN }}
+
       - name: "Run the action"
         uses: ./
         with: