Just upload the PR object itself

We don't know what secret info might end up in the context

.github/workflows/layered-build.yaml

@@ -20,12 +20,12 @@ jobs:
               with:
                 script: |
                     var fs = require('fs');
-                    fs.writeFileSync('${{github.workspace}}/context.json', JSON.stringify(context));
-            - name: Upload Context
+                    fs.writeFileSync('${{github.workspace}}/pr.json', JSON.stringify(context.payload.pull_request));
+            - name: Upload PR Info
               uses: actions/upload-artifact@v2
               with:
-                  name: context.json
-                  path: context.json
+                  name: pr.json
+                  path: pr.json
                   # We'll only use this in a triggered job, then we're done with it
                   retention-days: 1