Use more recent node version for js building

Signed-off-by: Julius Härtl <jus@bitgrid.net>

.drone.yml

@@ -70,7 +70,7 @@ pipeline:
       matrix:
         TESTS: syntax-php7.3
   eslint:
-    image: nextcloudci/jsunit:jsunit-5
+    image: node:lts-alpine
     commands:
       - npm install
       - npm run lint
@@ -78,7 +78,7 @@ pipeline:
       matrix:
         TESTS: eslint
   vue-build:
-    image: nextcloudci/jsunit:jsunit-5
+    image: node:lts-alpine
     commands:
       - npm install
       - npm run build