ci: attempt to fix DCT key

.github/workflows/build-publish-signed.yml

@@ -25,10 +25,13 @@ jobs:
         env:
           DOCKER_CONTENT_TRUST_REPOSITORY_PASSPHRASE: ${{ secrets.DCT_KEY_PASSPHRASE }}
           DCT_KEY_BASE64: ${{ secrets.DCT_KEY_BASE64 }}
+          DCT_KEY_ID: ${{ secrets.DCT_KEY_ID }}
         run: |
-          echo "$DCT_KEY_BASE64" | base64 -d > delegation.key
-          chmod 600 delegation.key
-          docker trust key load delegation.key --name gha
+          export DCT_KEY_PATH="$(echo "~/.docker/trust/private/${DCT_KEY_ID}.key")"
+          mkdir -p ~/.docker/trust/private
+          echo "$DCT_KEY_BASE64" | base64 -d > "$DCT_KEY_PATH"
+          chmod 600 "$DCT_KEY_PATH"
+          docker trust key load "$DCT_KEY_PATH" --name gha
 
       - name: Login to DockerHub
         uses: docker/login-action@v3
@@ -50,4 +53,8 @@ jobs:
           docker trust inspect --pretty ${{ env.IMAGE_NAME }}:${{ env.IMAGE_TAG }}
 
       - name: Remove DCT delegation key
-        run: rm delegation.key
+        env:
+          DCT_KEY_ID: ${{ secrets.DCT_KEY_ID }}
+        run: |
+          export DCT_KEY_PATH="$(echo "~/.docker/trust/private/${DCT_KEY_ID}.key")"
+          rm "$DCT_KEY_PATH"