Use originally extracted ref everywhere

Author: AndyTitu

.github/workflows/validate.yml

@@ -103,22 +103,16 @@ jobs:
       id: update-check-run
       if: ${{ always() }}
       env:
-        number: ${{ github.event.client_payload.pull_request.number }}
         job: ${{ github.job }}
+        ref: ${{ github.event.client_payload.pull_request.head.sha }}
         # Conveniently, job.status maps to https://developer.github.com/v3/checks/runs/#update-a-check-run
         conclusion: ${{ job.status }} 
       with:
         github-token: ${{ secrets.GITHUB_TOKEN }}
         script: |
-          const { data: pull } = await github.rest.pulls.get({
-            ...context.repo,
-            pull_number: process.env.number
-          });
-          const ref = pull.head.sha;
-
           const { data: checks } = await github.rest.checks.listForRef({
             ...context.repo,
-            ref
+            process.env.ref
           });
 
           const check = checks.check_runs.filter(c => c.name === process.env.job);