Dockerfile-updates (#47)

* Update how keys are fetched

See: nodejs/docker-node#2252

* Fix Dockerfile linting issues

Author: chorrell

14/Dockerfile

@@ -15,11 +15,12 @@ RUN set -ex \
     108F52B48DB57BB0CC439B2997B01419BD92F80A \
     B9E2F5981AA6E0CD28160D9FF13993A75599653C \
   ; do \
-    gpg --batch --keyserver hkps://keys.openpgp.org  --recv-keys "$key" ; \
+    { gpg --batch --keyserver hkps://keys.openpgp.org --recv-keys "$key" && gpg --batch --fingerprint "$key"; } || \
+    { gpg --batch --keyserver keyserver.ubuntu.com --recv-keys "$key" && gpg --batch --fingerprint "$key"; } ; \
   done
 
-ENV NPM_CONFIG_LOGLEVEL info
-ENV NODE_VERSION 14.17.1
+ENV NPM_CONFIG_LOGLEVEL=info
+ENV NODE_VERSION=14.17.1
 
 RUN curl -fsSLO --compressed "https://nodejs.org/dist/v$NODE_VERSION/node-v$NODE_VERSION-linux-x64.tar.xz" \
   && curl -fsSLO --compressed "https://nodejs.org/dist/v$NODE_VERSION/SHASUMS256.txt.asc" \