Update get-roots.yml

.github/workflows/get-roots.yml

@@ -2,10 +2,15 @@ name: Check for Google Root CA Updates
 
 on:
   push:
-    branches: [ master ]
+  pull_request:
   schedule:
     - cron: '23 23 * * *'
 
+defaults:
+  run:
+    shell: bash
+    working-directory: src
+
 jobs:
   check-apis:
     runs-on: ubuntu-latest