Update helm/chart-testing-action action to v2.8.0

.gitea/workflows/lint-test.yaml

@@ -171,7 +171,7 @@ jobs:
               | tail +2 | head -n -1 \
               | awk '{ print "helm repo add " $1 " " $3 }' \
               | while read cmd; do
-                if [[ "$cmd" == "helm repo add oci:*" ]]; then
+                if [[ "$cmd" == "*oci://*" ]]; then
                   echo ">> Ignoring OCI repo"
                 else
                   echo "$cmd" | sh;