add step to clear prior manifests

.gitea/workflows/render-manifests.yaml

@@ -37,6 +37,11 @@ jobs:
           token: ${{ secrets.GITEA_TOKEN }}
           version: v3.17.2 # Pending https://github.com/helm/helm/pull/30743
 
+      - name: Remove Prior Manifests
+        run: |
+          cd ${MANIFEST_DIR}/clusters
+          rm -rf ./*
+
       - name: Render Helm Manifests
         run: |
           for cluster in ${CLUSTERS}; do