fix: use node 14, same as github actions config

.woodpecker.yml

@@ -1,6 +1,6 @@
 pipeline:
     buildfrontend:
-        image: node
+        image: node:14
         commands:
             - yarn install
             - yarn test
@@ -9,7 +9,7 @@ pipeline:
             - yarn build
 
     deploy:
-        image: node
+        image: node:14
         when:
             event: push
             branch: master
@@ -18,6 +18,6 @@ pipeline:
         secrets: [gitea_write_deploy_key, librepages_deploy_secret]
 
     lint-frontend:
-        image: node
+        image: node:14
         commands:
             - yarn lint-ci