fix: helm-conftest step

Signed-off-by: Brenno Oliveira <brenno.oliveira@deliveryhero.com>

.github/workflows/helm-conftest.yaml

@@ -5,10 +5,18 @@ jobs:
     name: Run conftest for all charts
     runs-on: ubuntu-latest
     container:
-      image: instrumenta/helm-conftest:latest
+      image: alpine/helm:latest
     steps:
       - name: Checkout Code
         uses: actions/checkout@v4.1.7
 
+      - name: Install Conftest
+        run: |
+          apk add --no-cache curl
+          curl -L https://github.com/open-policy-agent/conftest/releases/latest/download/conftest-linux-amd64.tar.gz -o conftest.tar.gz
+          tar xzf conftest.tar.gz
+          mv conftest /usr/local/bin/
+          rm conftest.tar.gz
+
       - name: Validate all charts
         run: bash ci/helm-conftest.sh