feat!: add helm plugins

Author: fredleger

images/ci-helm/Dockerfile

@@ -5,6 +5,21 @@ LABEL org.opencontainers.image.source="https://github.com/hoverkraft-tech/docker
 
 # we can probably ignore warning about versions of such packages
 # hadolint ignore=DL3018
-RUN apk add --no-cache jq yq curl openssl git
+RUN --mount=type=cache,target=/var/cache/apt \
+  set -ex \
+  apk add jq yq curl openssl git
 
 COPY scripts/ /usr/local/bin/
+
+RUN \
+  set ex; \
+  addgroup -g 1000 helm && \
+  adduser -u 1000 -G helm -s /bin/ash -D helm
+
+USER helm:helm
+WORKDIR /home/helm
+
+RUN --mount=type=cache,target=/home/.cache \
+  set -ex; \
+  helm plugin install https://github.com/jtyr/kubeconform-helm --version 0.1.17; \
+  helm plugin install https://github.com/losisin/helm-values-schema-json.git --version 1.6.4;