using ubuntu pandoc package

this prevents version tracking

Signed-off-by: Martin Alfke <ma@betadots.de>

Author: tuxmea

.github/workflows/build.yaml

@@ -74,8 +74,7 @@ jobs:
           bundler-cache: true
       - name: Install pandoc
         run: |
-          curl -sLO https://github.com/jgm/pandoc/releases/download/3.9.0.2/pandoc-3.9.0.2-1-amd64.deb
-          sudo dpkg -i pandoc-3.9.0.2-1-amd64.deb
+          sudo apt install -y pandoc
       - name: Build website
         run: |
           bundle exec rake references:openfact INSTALLPATH=docs