fix: install helm via installation script

Dockerfile

@@ -2,10 +2,15 @@ FROM docker.io/library/alpine:3.14
 
 ARG HELM_VERSION
 
-COPY install.sh /install.sh
-RUN VERSION=${HELM_VERSION} /install.sh
+RUN apk add bash curl git openssl && \
+    curl https://raw.githubusercontent.com/helm/helm/main/scripts/get-helm-3 --output /tmp/install.sh
+
+RUN [[ ${HELM_VERSION} == "" ]]; bash /tmp/install.sh
+RUN [[ ${HELM_VERSION} != "" ]]; bash /tmp/install.sh --version ${HELM_VERSION}
+
+RUN rm /tmp/install.sh
 
 # Install additionally cm-push plugin
 RUN helm plugin install https://github.com/chartmuseum/helm-push.git
 
-ENTRYPOINT [ "/usr/bin/helm" ]
+ENTRYPOINT [ "/usr/local/bin/helm" ]