fix: installing chartpress in publish chart action (#68)

publish-chart/Dockerfile

@@ -1,14 +1,15 @@
-FROM docker:20.10.5
+FROM bitnami/kubectl:1.25-debian-11
 
+USER root
 # install dependencies
-# Note: Chartpress 0.7.0 is the latest version compatible until https://github.com/jupyterhub/chartpress/issues/118 is fixed
-RUN apk add git python3 py-pip && \
+RUN apt-get update && apt-get install -y git python3 python3-pip wget && \
     wget -O /usr/bin/yq "https://github.com/mikefarah/yq/releases/download/3.1.1/yq_linux_amd64" && \
     chmod 0755 /usr/bin/yq && \
-    pip3 install -U pip chartpress==0.7.0 && \
+    pip3 install -U pip chartpress==2.1.0 && \
     wget -O /tmp/helm.tar.gz "https://get.helm.sh/helm-v3.5.2-linux-amd64.tar.gz" && \
     tar -xf /tmp/helm.tar.gz --strip-components=1 -C /usr/bin/ && \
-    chmod 0755 /usr/bin/helm
+    chmod 0755 /usr/bin/helm && \
+    rm -rf /var/lib/apt/lists/*
 
 COPY publish-chart.sh /
 ENTRYPOINT [ "/publish-chart.sh" ]