Add kubectl 1.17/Helm 3.5.2-based image

Signed-off-by: Takuya Noguchi <takninnovationresearch@gmail.com>

Dockerfile.gitlab-helm3.5-kubectl1.17

@@ -0,0 +1,27 @@
+FROM ruby:3.0.0-alpine
+MAINTAINER GitLab Engineering Productivity Team
+
+ENV KUBECTL_VERSION=1.17.17
+
+ENV HELM_VERSION=3.5.3
+ENV HELM_URL=https://get.helm.sh/helm-v${HELM_VERSION}-linux-amd64.tar.gz
+ENV HELM_HOME=/root/.helm
+
+# Install dependencies
+RUN apk --no-cache -U add openssl curl tar gzip bash ca-certificates git \
+  && mkdir -p /opt
+
+# Install kubectl
+RUN wget https://dl.k8s.io/release/v${KUBECTL_VERSION}/bin/linux/amd64/kubectl \
+  && install -o root -g root -m 0755 kubectl /usr/local/bin/kubectl \
+  && rm -f kubectl
+
+# Install Helm
+RUN wget -q -O - ${HELM_URL} | tar zxf - \
+  && mv linux-amd64/helm /usr/bin/ \
+  && chmod +x /usr/bin/helm \
+  && helm version --client
+
+# Install kubeval
+RUN mkdir -p $HELM_HOME/plugins \
+  && helm plugin install https://github.com/instrumenta/helm-kubeval