chore(ci): update to actions/checkout@v6 (#819)

Author: tottoto

.github/workflows/ci.yml

@@ -28,7 +28,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Checkout
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
 
       - name: Install Rust
         uses: dtolnay/rust-toolchain@stable
@@ -55,7 +55,7 @@ jobs:
 
     steps:
       - name: Checkout
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
 
       - name: Install Rust (${{ matrix.rust }})
         uses: dtolnay/rust-toolchain@master
@@ -74,7 +74,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Checkout
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
 
       - name: Get MSRV from package metadata
         id: metadata
@@ -99,7 +99,7 @@ jobs:
 
     steps:
       - name: Checkout
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
 
       - name: Install Rust
         uses: dtolnay/rust-toolchain@stable
@@ -112,7 +112,7 @@ jobs:
   minimal-versions:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
       - uses: dtolnay/rust-toolchain@nightly
       - uses: dtolnay/rust-toolchain@stable
       - uses: taiki-e/install-action@cargo-hack
@@ -125,7 +125,7 @@ jobs:
 
     steps:
       - name: Checkout
-        uses: actions/checkout@v5
+        uses: actions/checkout@v6
 
       - name: Install Rust
         uses: dtolnay/rust-toolchain@nightly
@@ -139,7 +139,7 @@ jobs:
     name: semver
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@v6
       - name: Check semver
         uses: obi1kenobi/cargo-semver-checks-action@v2
         with: