Change to larger instance

Summary:
Changes to use the 32-core-ubuntu machine from the standard set of runners
available to Meta OSS projects https://fburl.com/opensource/er6f7t47.

Reviewed By: srikrishnagopu

Differential Revision: D61275375

fbshipit-source-id: 5fe208c1bfdfde76e6b021063ddcab90781e3c9e

.github/workflows/github-actions-demo.yml

@@ -3,7 +3,7 @@ run-name: ${{ github.actor }} is testing out GitHub Actions 🚀
 on: [push]
 jobs:
   Explore-GitHub-Actions:
-    runs-on: ubuntu-latest
+    runs-on: 32-core-ubuntu 
     steps:
       - run: echo "🎉 The job was automatically triggered by a ${{ github.event_name }} event."
       - run: echo "🐧 This job is now running on a ${{ runner.os }} server hosted by GitHub!"