fix(Dockerfile): update shell script to v4

The pre-installed plugins must be installed individually. Otherwise runs this
project into the problem, that we need to trigger a new release of the container
image only to update the plugin in case of an issue.

Dockerfile

@@ -3,16 +3,11 @@ FROM docker.io/library/alpine:3.22.2
 ARG HELM_VERSION
 
 RUN apk add bash curl git openssl && \
-    curl https://raw.githubusercontent.com/helm/helm/main/scripts/get-helm-3 --output /tmp/install.sh
+    curl https://raw.githubusercontent.com/helm/helm/main/scripts/get-helm-4 --output /tmp/install.sh
 
 RUN if [[ -z "${HELM_VERSION+x}" ]]; then bash /tmp/install.sh; fi
 RUN if [[ -n "${HELM_VERSION+x}" ]]; then bash /tmp/install.sh --version "${HELM_VERSION}"; fi
 
 RUN rm /tmp/install.sh
 
-# Install additionally helm plugins
-RUN helm plugin install https://github.com/chartmuseum/helm-push.git && \
-    helm plugin install https://github.com/helm-unittest/helm-unittest.git && \
-    helm plugin install https://github.com/losisin/helm-values-schema-json.git
-
 ENTRYPOINT [ "/usr/local/bin/helm" ]

Makefile

@@ -1,6 +1,6 @@
 # HELM_VERSION
 # Only required to install a specify version
-HELM_VERSION?=v3.19.0 # renovate: datasource=github-releases depName=helm/helm
+HELM_VERSION?=v4.0.0 # renovate: datasource=github-releases depName=helm/helm
 
 # CONTAINER_RUNTIME
 # The CONTAINER_RUNTIME variable will be used to specified the path to a

README.md

@@ -7,7 +7,7 @@ goal of this project is to package the binary `helm` as container image and prov
 The source code of the binary can be found in the upstream project of [helm](github.com/helm/helm).
 
 ```bash
-IMAGE_VERSION=3.19.0
+IMAGE_VERSION=4.0.0
 docker run \
   --rm \
   --volume "$(pwd):$(pwd)" \