fix(ci): Don't deploy docs on PRs from forks, fixes #923 (#924)

Author: lorensr

.github/workflows/ci.yml

@@ -102,7 +102,8 @@ jobs:
         if: ${{ github.ref == 'refs/heads/main' }}
         run: npx vercel deploy packages/docs/build -t ${{ secrets.VERCEL_TOKEN }} --name typescript --scope temporal --prod --yes
       - name: Deploy draft docs
-        if: ${{ github.ref != 'refs/heads/main' }}
+        # Don't run on forks, since secrets won't be available, and command will fail
+        if: ${{ github.event_name == 'pull_request' && github.event.pull_request.head.repo.full_name == github.repository && github.ref != 'refs/heads/main' }}
         run: npx vercel deploy packages/docs/build -t ${{ secrets.VERCEL_TOKEN }} --name typescript --scope temporal --yes
 
   # Run TS linting and ts-prune to find unused code