build(docker): Optimize Docker image layers/caching & bump node to 14.15 (#776)

* refactor(docker): Combine RUN statements to reduce number of image layers

* Add --update && --no-cache to apk add command

* Combine RUN statements in first stage

* Consolidate COPY commands from BUILD_IMAGE

* Add docs & snap to .dockerignore

* Revert first COPY statement in 2nd stage

* Write committag.json in first stage & only do one COPY
Also pin base image Alpine version, and add Docker & GitHub Actions update monitoring via Dependabot

* Bump node to 14.15.4

* Change base image to node:14.15-alpine and remove Dependabot Docker monitoring

* Changes in response to PR comments

* Remove ARG/ENV statements from second build stage

Dockerfile

@@ -1,4 +1,4 @@
-FROM node:12.18-alpine AS BUILD_IMAGE
+FROM node:14.15-alpine AS BUILD_IMAGE
 
 ARG COMMIT_TAG
 ENV COMMIT_TAG=${COMMIT_TAG}
@@ -11,25 +11,21 @@ RUN yarn --frozen-lockfile && \
 
 # remove development dependencies
 RUN yarn install --production --ignore-scripts --prefer-offline
-RUN yarn cache clean
 
-FROM node:12.18-alpine
-
-ARG COMMIT_TAG
-ENV COMMIT_TAG=${COMMIT_TAG}
-
-RUN apk add tzdata
-
-COPY . /app
-WORKDIR /app
-
-# copy from build image
-COPY --from=BUILD_IMAGE /app/dist ./dist
-COPY --from=BUILD_IMAGE /app/.next ./.next
-COPY --from=BUILD_IMAGE /app/node_modules ./node_modules
+RUN rm -rf src && \
+  rm -rf server
 
 RUN echo "{\"commitTag\": \"${COMMIT_TAG}\"}" > committag.json
 
+
+FROM node:14.15-alpine
+
+RUN apk add --no-cache tzdata
+
+# copy from build image
+COPY --from=BUILD_IMAGE /app /app
+WORKDIR /app
+
 CMD yarn start
 
 EXPOSE 5055