Fix: Switch from distroless to node:alpine image

Chrome (via Puppeteer) misses a shared library on distroless.
To fix this, switch to node:12-alpine

Dockerfile

@@ -12,7 +12,9 @@ WORKDIR /build
 RUN npm ci --only=production
 
 # Create hardened runtime image
-FROM gcr.io/distroless/nodejs:12
+# Distroless seems to not work with puppeteer: "chrome: error while loading shared libraries: libgobject-2.0.so.0"
+# FROM gcr.io/distroless/nodejs:12
+FROM node:12-alpine
 COPY --from=build-env-server /build /app
 COPY --from=build-env-webapp /build/public /app/public
 WORKDIR /app