Upgrade GitHub actions to node 18.x

Author: jtraulle

.github/workflows/documentation.yml

@@ -14,7 +14,7 @@ jobs:
       - uses: actions/checkout@v1
       - uses: actions/setup-node@v1
         with:
-          node-version: '14.x'
+          node-version: '18.x'
       - name: Test Build
         run: |
           if [ -e yarn.lock ]; then
@@ -32,7 +32,7 @@ jobs:
       - uses: actions/checkout@v1
       - uses: actions/setup-node@v1
         with:
-          node-version: '14.x'
+          node-version: '18.x'
       - uses: webfactory/[email protected]
         with:
           ssh-private-key: ${{ secrets.GH_PAGES_DEPLOY }}