run CI on all branches, not only "main"

Author: moritz-gross

.github/workflows/python.yml

@@ -1,10 +1,6 @@
 name: Python
 
-on:
-  push:
-    branches: [ "main" ]
-  pull_request:
-    branches: [ "main" ]
+on: [push, pull_request]
 
 jobs:
   test:

.github/workflows/rust.yml

@@ -1,10 +1,6 @@
 name: Rust
 
-on:
-  push:
-    branches: [ "main" ]
-  pull_request:
-    branches: [ "main" ]
+on: [push, pull_request] # note: pre-release job still only on 'refs/heads/main'
 
 env:
   CARGO_TERM_COLOR: always