chore: Update Dockerfile environment variables using the = syntax i…

…nstead of the space syntax.

Dockerfile

@@ -22,7 +22,7 @@ COPY . .
 # Next.js collects completely anonymous telemetry data about general usage.
 # Learn more here: https://nextjs.org/telemetry
 # Uncomment the following line in case you want to disable telemetry during the build.
-ENV NEXT_TELEMETRY_DISABLED 1
+ENV NEXT_TELEMETRY_DISABLED=1
 
 COPY .env.$INSTANCE .env
 RUN npm run build
@@ -32,7 +32,7 @@ FROM ${VARIANT} AS runner
 ARG INSTANCE=production
 WORKDIR /app
 
-ENV NODE_ENV production
+ENV NODE_ENV=production
 # Uncomment the following line in case you want to disable telemetry during runtime.
 # ENV NEXT_TELEMETRY_DISABLED 1
 
@@ -50,7 +50,7 @@ COPY .env.$INSTANCE .env
 
 EXPOSE 3000
 
-ENV PORT 3000
-ENV HOSTNAME localhost
+ENV PORT=3000
+ENV HOSTNAME=localhost
 
 CMD ["node", "server.js"]