Refactor CI workflow triggers for better coverage

Updated CI workflow to include pull requests and workflow dispatch.

Author: ViralBShah

.github/workflows/ci.yml

@@ -2,13 +2,11 @@ name: CI
 env:
   JULIA_NUM_THREADS: 2
 on:
-  pull_request:
-    branches:
-      - master
   push:
-    branches:
-      - master
-    tags: '*'
+    branches: [master]
+    tags: ['*']
+  pull_request:
+  workflow_dispatch:
 jobs:
   test:
     name: Julia ${{ matrix.version }} - ${{ matrix.os }} - ${{ matrix.arch }} - ${{ github.event_name }}