fix: switch to Hugo Modules setup

Author: alee

.github/workflows/gh-pages.yml

@@ -10,22 +10,17 @@ on:
 
 jobs:
   deploy:
-    runs-on: ubuntu-20.04
+    runs-on: ubuntu-22.04
     steps:
-      - uses: actions/checkout@v2
-        with:
-          submodules: 'recursive'
-          fetch-depth: 0
-
-      - name: Setup Yarn
-        uses: actions/setup-node@v2
-      - run: yarn install
+      - uses: actions/checkout@v3
 
       - name: Read .env hugo version
         id: hugo-version
         run: |
           . ./.env
           echo "::set-output name=HUGO_VERSION::${HUGO_VERSION}"
+          hugo mod init github.com/openmodelingfoundation/openmodelingfoundation.github.io
+          hugo mod get github.com/google/docsy@v0.4.0
 
       - name: Setup Hugo 
         uses: peaceiris/actions-hugo@v2