Fix python installation in alpine image

Dockerfile

 # File: docker_phx/Dockerfile
-FROM elixir:1.9-alpine as build
+FROM elixir:1.11-alpine as build
 
 # install build dependencies
-RUN apk add --update git build-base nodejs npm yarn python
+RUN apk add --update --no-cache build-base npm git py-pip
 
 RUN mkdir /app
 WORKDIR /app
@@ -36,7 +36,7 @@ RUN mix compile
 RUN mix release
 
 # prepare release image
-FROM alpine:3.9 AS app
+FROM alpine:3.13 AS app
 
 # install runtime dependencies
 RUN apk add --update bash openssl postgresql-client
@@ -50,7 +50,7 @@ WORKDIR /app
 
 
 # copy release to app container
-COPY --from=build /app/_build/prod/rel/docker_phx .
+COPY --from=build /app/_build/prod/rel/diskuy .
 COPY entrypoint.sh .
 RUN chown -R nobody: /app
 USER nobody