Update Docker base image to node 18 (#291)

Author: barryadk

.github/action/entrypoint.sh

@@ -1,5 +1,4 @@
 #!/bin/sh
 output=$(/cli/bin/run $*); status=$?;
-echo "::set-output name=response::
-$output"
-exit $status
+echo "response=$output" >> $GITHUB_OUTPUT
+exit $status

Dockerfile

@@ -1,4 +1,4 @@
-FROM node:12-alpine
+FROM node:18-alpine
 WORKDIR /cli
 COPY package*.json ./
 COPY ./bin ./bin