#1 Move documentation from Confluence to Git

* add workflow_dispatch event to enable manual CI build
* update checkout action to v4
* update NodeJS to 18

Author: oliverlietz

.github/workflows/documentation.yml

@@ -3,15 +3,16 @@ name: "Documentation"
 on:
   push:
     branches: [ main ]
+  workflow_dispatch:
 
 jobs:
   build:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
       - uses: actions/setup-node@v3
         with:
-          node-version: '16'
+          node-version: '18'
       - run: npm i antora @antora/lunr-extension
       - run: npx --fetch antora antora-playbook.yml
       - uses: peaceiris/actions-gh-pages@v3