Change CI build triggers

Now builds on pushes to master and any pull request

Author: saxbophone

.github/workflows/continuous-integration.yml

@@ -1,6 +1,10 @@
 name: continuous-integration
 
-on: pull_request
+on:
+  push:
+    branches:
+      - master
+  pull_request:
 
 jobs:
   build: