Use node:12 as build docker image

.gitlab-ci.yml

@@ -26,7 +26,7 @@ test:php:
         - php-cs-fixer fix --dry-run --config=Build/.php_cs --diff --diff-format=udiff
 
 build:
-  image: node:9
+  image: node:12
   stage: build
   before_script:
     - npm config set cache cache/npm/ --global

Configuration/GitLab/t3o-builds.yml

@@ -61,7 +61,7 @@ build:
 
 layout:
   stage: layout
-  image: node:8
+  image: node:12
   before_script:
   - cd private/typo3conf/ext/t3olayout/Build
   script: