Update Pandoc installation method in generate-sdk workflow

Changed the method of installing Pandoc in the generate-sdk workflow. Instead of using apt-get to install, we download the Pandoc package directly via curl and install it using dpkg. This ensures we are using the latest version of Pandoc, which could potentially fix issues related to document conversion.

.github/workflows/generate-sdk.yaml

@@ -61,7 +61,9 @@ jobs:
 
           python3 ./__main__.py -p ./temp -n "$namespace"
       - name: Install Pandoc
-        run: sudo apt-get update && sudo apt-get install pandoc
+        run: |
+          curl -O -L https://github.com/jgm/pandoc/releases/download/3.1.8/pandoc-3.1.8-1-amd64.deb
+          dpkg -i *.deb
       - name: Format docs
         working-directory: expediagroup/sdk/docsgen/docs
         run: |