Bump actions/checkout from 3 to 4 (#50)

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)

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

Signed-off-by: dependabot[bot] <[email protected]>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

.github/workflows/ci.yaml

@@ -17,7 +17,7 @@ jobs:
         - beta
         - 1.69.0 # MSRV
     steps:
-    - uses: actions/checkout@v3
+    - uses: actions/checkout@v4
     - uses: IronCoreLabs/rust-toolchain@v1
       with:
         toolchain: ${{ matrix.rust_version }}
@@ -35,7 +35,7 @@ jobs:
         - x86_64-unknown-linux-musl # Alpine Linux x86_64
         - wasm32-unknown-unknown
     steps:
-    - uses: actions/checkout@v3
+    - uses: actions/checkout@v4
     - uses: IronCoreLabs/rust-toolchain@v1
       with:
         targets: ${{ matrix.target }}
@@ -54,7 +54,7 @@ jobs:
         - aarch64-apple-ios
         - x86_64-apple-darwin # 64-bit OSX
     steps:
-    - uses: actions/checkout@v3
+    - uses: actions/checkout@v4
     - uses: IronCoreLabs/rust-toolchain@v1
       with:
         targets: ${{ matrix.target }}
@@ -72,7 +72,7 @@ jobs:
         target:
         - x86_64-pc-windows-msvc
     steps:
-    - uses: actions/checkout@v3
+    - uses: actions/checkout@v4
     - uses: IronCoreLabs/rust-toolchain@v1
       with:
         targets: ${{ matrix.target }}
@@ -90,7 +90,7 @@ jobs:
         - stable
         - 1.69.0
     steps:
-    - uses: actions/checkout@v3
+    - uses: actions/checkout@v4
     - uses: IronCoreLabs/rust-toolchain@v1
       with:
         toolchain: ${{ matrix.rust_version }}
@@ -106,7 +106,7 @@ jobs:
         rust_version:
         - stable
     steps:
-    - uses: actions/checkout@v3
+    - uses: actions/checkout@v4
     - uses: IronCoreLabs/rust-toolchain@v1
       with:
         toolchain: ${{ matrix.rust_version }}
@@ -120,7 +120,7 @@ jobs:
         rust_version:
         - nightly
     steps:
-    - uses: actions/checkout@v3
+    - uses: actions/checkout@v4
     - uses: IronCoreLabs/rust-toolchain@v1
       with:
         toolchain: ${{ matrix.rust_version }}