Use ENV key=value in Dockerfile templates

resources/templates/node/Dockerfile.template

@@ -1,5 +1,5 @@
 FROM node:12.18-alpine
-ENV NODE_ENV production
+ENV NODE_ENV=production
 WORKDIR /usr/src/app
 COPY ["package.json", "package-lock.json*", "npm-shrinkwrap.json*", "./"]
 RUN npm install --production --silent && mv node_modules ../

resources/templates/python/Dockerfile.template

@@ -12,10 +12,10 @@ EXPOSE {{ . }}
 
 {{/if}}
 # Keeps Python from generating .pyc files in the container
-ENV PYTHONDONTWRITEBYTECODE 1
+ENV PYTHONDONTWRITEBYTECODE=1
 
 # Turns off buffering for easier container logging
-ENV PYTHONUNBUFFERED 1
+ENV PYTHONUNBUFFERED=1
 
 # Install pip requirements
 ADD requirements.txt .