Bump actions/checkout from 1 to 4

Bumps [actions/checkout](https://github.com/actions/checkout) from 1 to 4.
- [Release notes](https://github.com/actions/checkout/releases)
- [Changelog](https://github.com/actions/checkout/blob/main/CHANGELOG.md)
- [Commits](actions/checkout@v1...v4)

---
updated-dependencies:
- dependency-name: actions/checkout
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <[email protected]>

.github/workflows/ci.yml

@@ -17,7 +17,7 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
-    - uses: actions/checkout@v2
+    - uses: actions/checkout@v4
 
     - name: Setup Development Environment
       uses: ./.github/actions/ka3005p-dev

.github/workflows/rust.yml

@@ -24,7 +24,7 @@ jobs:
             suffix: .exe # Windows has an .exe suffix
 
     steps:
-    - uses: actions/checkout@v2
+    - uses: actions/checkout@v4
 
     - name: Install Rust
       uses: actions-rs/toolchain@v1
@@ -72,7 +72,7 @@ jobs:
   clippy_check:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v1
+      - uses: actions/checkout@v4
       - name: Install Rust
         uses: actions-rs/toolchain@v1
         with:
@@ -90,7 +90,7 @@ jobs:
     name: rustfmt
     runs-on: ubuntu-latest
     steps:
-    - uses: actions/checkout@v2
+    - uses: actions/checkout@v4
     - name: Install Rust
       uses: actions-rs/toolchain@v1
       with:
@@ -105,7 +105,7 @@ jobs:
   rustdoc:
     runs-on: ubuntu-latest
     steps:
-    - uses: actions/checkout@v2
+    - uses: actions/checkout@v4
 
     - name: Install Rust toolchain
       uses: actions-rs/toolchain@v1