ui: update versions for the Elm components (#2482)

The frontend CI job started to fail for some obscure reasons, most
probably because we use a very old version of NodeJS.

To make it work again, this change does the following:

* Bump to the latest NodeJS LTS version and use the buster variant.
* Use Yarn instead of npm to install Javascript packages.
* Bump Elm components to their latest versions.

There should be no functional change to the UI code.

Signed-off-by: Simon Pasquier <spasquie@redhat.com>

ui/Dockerfile

@@ -1,7 +1,12 @@
-FROM node:6.10
+# elm-format only works with buster variants of the NodeJS container image.
+# See https://github.com/avh4/elm-format/issues/709 for more details.
+FROM node:14-buster
 
-RUN npm install -g \
-  elm@0.19.0 \
-  elm-format@0.8.0 \
-  elm-test@0.19.0-beta5 \
+ENV NPM_CONFIG_PREFIX=/home/node/.npm-global
+ENV PATH=$PATH:/home/node/.npm-global/bin
+
+RUN mkdir -p $NPM_CONFIG_PREFIX; yarn global add \
+  elm@0.19.1 \
+  elm-format@0.8.4 \
+  elm-test@0.19.1-revision6 \
   uglify-js@3.4.7

ui/app/elm.json

@@ -3,7 +3,7 @@
     "source-directories": [
         "src"
     ],
-    "elm-version": "0.19.0",
+    "elm-version": "0.19.1",
     "dependencies": {
         "direct": {
             "elm/browser": "1.0.0",