Dockerfile: delete dead ENV

Dockerfile

@@ -4,9 +4,9 @@ LABEL [email protected]
 
 # - - - - - - - - - - - - - - - -
 # install ruby+
-# tar is needed to tar-pipe test coverage out of tmpfs.
-# tini is needed for pid-1 zombie reaping
-# Install util-linux to use `script` to allow ECS exec logging
+# - tar is needed to tar-pipe test coverage out of tmpfs.
+# - tini is needed for pid-1 zombie reaping
+# - util-linux to use `script` to allow ECS exec logging
 # - - - - - - - - - - - - - - - -
 
 RUN apk --update --upgrade --no-cache add \
@@ -17,10 +17,6 @@ RUN apk --update --upgrade --no-cache add \
     tini \
     util-linux
 
-# - - - - - - - - - - - - - - - -
-# install ruby gems
-# - - - - - - - - - - - - - - - -
-
 WORKDIR /app
 COPY Gemfile .
 
@@ -33,7 +29,6 @@ RUN apk --update --upgrade add --virtual build-dependencies build-base \
 
 ARG COMMIT_SHA
 ENV SHA=${COMMIT_SHA}
-ENV COMMIT_SHA=${COMMIT_SHA}
 
 # ARGs are reset after FROM See https://github.com/moby/moby/issues/34129
 ARG BASE_IMAGE