run workflow only on main

.github/workflows/rust.yml

@@ -1,6 +1,7 @@
 name: Rust
 on:
   push:
+    branches: ["main"]
     paths:
       - '**.*.rs'
       - 'src/**'

.github/workflows/typos.yml

@@ -1,7 +1,10 @@
 name: Check for typos
 
 on:
-  [push, pull_request, workflow_dispatch]
+  push:
+    branches: ["main"]
+  pull_request:
+  workflow_dispatch:
 
 jobs:
   check-typos: