Bump actions/checkout from 3 to 4 (#935)

Bumps [actions/checkout](https://github.com/actions/checkout) from 3 to
4.
- [Release notes](https://github.com/actions/checkout/releases)
-
[Changelog](https://github.com/actions/checkout/blob/main/CHANGELOG.md)
- [Commits](actions/checkout@v3...v4)

.github/workflows/build-ksud.yml

@@ -2,13 +2,13 @@ name: Build KSUD
 on:
   push:
     branches: [ "main", "ci" ]
-    paths: 
+    paths:
       - '.github/workflows/build-ksud.yml'
       - '.github/workflows/ksud.yml'
       - 'userspace/ksud/**'
   pull_request:
     branches: [ "main" ]
-    paths: 
+    paths:
       - '.github/workflows/build-ksud.yml'
       - '.github/workflows/ksud.yml'
       - 'userspace/ksud/**'