ci: do not trigger on every branch

.github/workflows/build.yml

@@ -1,6 +1,12 @@
 name: Build
 
-on: [push, pull_request, workflow_dispatch]
+on:
+  push:
+    branches:
+      - "main"
+  pull_request:
+    branches:
+      - "main"
 
 jobs:
   windows:

.github/workflows/feature-matrix.yml

@@ -1,6 +1,12 @@
 name: Feature matrix
 
-on: [push, pull_request, workflow_dispatch]
+on:
+  push:
+    branches:
+      - "main"
+  pull_request:
+    branches:
+      - "main"
 
 jobs:
   windows_msvc_x64:

.github/workflows/unit.yml

@@ -1,6 +1,12 @@
 name: Unit
 
-on: [push, pull_request, workflow_dispatch]
+on:
+  push:
+    branches:
+      - "main"
+  pull_request:
+    branches:
+      - "main"
 
 jobs:
   teal_lua_consistency: