update node version

Author: JeremyDolle

.github/workflows/documentation.yml

@@ -27,7 +27,7 @@ jobs:
       - uses: actions/checkout@v1
       - uses: actions/setup-node@v1
         with:
-          node-version: '12.x'
+          node-version: '14.x'
       - name: Add key to allow access to repository
         env:
           SSH_AUTH_SOCK: /tmp/ssh_agent.sock