get the pr number a different way?

.github/workflows/sage-test.yml

@@ -16,6 +16,14 @@ jobs:
     steps:
       - name: Checkout
         uses: actions/checkout@v3
+      - name: Get PR number
+        uses: actions/github-script@v4
+        with:
+          github-token: ${{ github.token }}
+          script: |
+            const core = require('@actions/core');
+            const pr = context.payload.number;
+            core.exportVariable('PR_NUMBER', pr);
       - name: Setup PHP
         uses: shivammathur/setup-php@v2
         with:
@@ -37,7 +45,7 @@ jobs:
           esac
 
           php_short=$(echo "${{ matrix.php-version }}" | tr -d '.')
-          pr_num=$(echo "${{ github.event.number }}")
+          pr_num=$PR_NUMBER
 
           multidev_name="${os_short}-${php_short}-${pr_num}"
           echo "Generated multidev name: $multidev_name"