Add SOPS support

Dockerfile

@@ -7,6 +7,12 @@ ARG TARGETARCH
 ADD https://get.helm.sh/helm-v${HELM_VERSION}-linux-${TARGETARCH}.tar.gz /tmp/tarballs/
 RUN tar zxvf /tmp/tarballs/*.tar.gz -C /usr/local/bin/ --strip-components=1 linux-${TARGETARCH}/helm
 
+# sops: encrypting secrets
+FROM ubuntu:22.04 as sops
+ARG SOPS_VERSION=3.8.1
+ARG ARCH=amd64
+ADD --chmod=755 https://github.com/getsops/sops/releases/download/v${SOPS_VERSION}/sops-v${SOPS_VERSION}.linux.$ARCH /usr/local/bin/sops
+
 FROM node:16-bullseye-slim
 
 # We need to set a home directory, since both Helm and NPM won't be able to write to /.
@@ -15,6 +21,7 @@ ENV HOME=/tmp/argocd-cdk8s-plugin/
 RUN mkdir $HOME && chmod 770 $HOME
 RUN apt-get update && apt-get install git tree ca-certificates -y --no-install-recommends && rm -rf /var/lib/apt/lists/*
 COPY --from=helm /usr/local/bin/ /usr/local/bin/
+COPY --from=sops /usr/local/bin/ /usr/local/bin/
 COPY plugin.yaml /home/argocd/cmp-server/config/plugin.yaml
 COPY scripts/* /