Run CI for pull requests. (#159)

.github/workflows/main.yml

@@ -4,17 +4,17 @@ name: CI
 
 # Controls when the workflow will run
 on:
+  pull_request:
+
   push:
     # Sequence of patterns matched against refs/tags
     branches: ["master"]
 
-
   # Allows you to run this workflow manually from the Actions tab
   workflow_dispatch:
 
 # A workflow run is made up of one or more jobs that can run sequentially or in parallel
 jobs:
-  # This workflow contains a single job called "build"
   run-tests-dev:
     # The type of runner that the job will run on
     runs-on: ubuntu-latest