Merge pull request #565 from taiki-e/checkout

Update actions/checkout action to v4

Author: Amanieu

.github/workflows/main.yml

@@ -80,7 +80,7 @@ jobs:
           os: windows-latest
           rust: nightly-x86_64-gnu
     steps:
-    - uses: actions/checkout@v1
+    - uses: actions/checkout@v4
       with:
         submodules: true
     - name: Install Rust (rustup)
@@ -108,7 +108,7 @@ jobs:
     name: Rustfmt
     runs-on: ubuntu-latest
     steps:
-    - uses: actions/checkout@v1
+    - uses: actions/checkout@v4
       with:
         submodules: true
     - name: Install stable `rustfmt`
@@ -119,7 +119,7 @@ jobs:
     name: Clippy
     runs-on: ubuntu-latest
     steps:
-    - uses: actions/checkout@v1
+    - uses: actions/checkout@v4
       with:
         submodules: true
     # Unlike rustfmt, stable clippy does not work on code with nightly features.