Update ci.yml

Add a workflow dispatch item to ci.yml

Author: andreasnoack

.github/workflows/ci.yml

@@ -7,6 +7,7 @@ on:
     branches:
       - master
     tags: '*'
+  workflow_dispatch:
 jobs:
   test:
     name: Julia ${{ matrix.version }} - ${{ matrix.os }} - ${{ matrix.arch }} - ${{ github.event_name }}