will run tests on pull requests in github actions

Author: GarimaB06

.github/workflows/jest.yml

@@ -1,5 +1,9 @@
 name: Jest
-on: push
+on: 
+  pull_request:
+    types: [opened, edited, reopened, synchronize]
+    branches:
+      - dev
 jobs:
   test:
     runs-on: ubuntu-latest