ci: Remove branch restrictions

There's no reason to restrict branches; downstream developers often do
work on branches that are not "main" and it's nice for the actions to
run there also

.github/workflows/ci.yml

@@ -2,10 +2,8 @@
 name: Test bmaptool
 
 on:
-  push:
-    branches: [ "main" ]
-  pull_request:
-    branches: [ "main" ]
+  - push
+  - pull_request
 
 jobs:
   test: