Upgrade GitHub actions to v4.

Author: gendx

.github/workflows/benches.yml

@@ -7,7 +7,7 @@ jobs:
       RUSTFLAGS: "-D warnings"
       CARGO_UNSTABLE_SPARSE_REGISTRY: true
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
       - uses: dtolnay/rust-toolchain@nightly
       - name: Build benches
         run: cargo build --benches --verbose

.github/workflows/codecov.yml

@@ -4,7 +4,7 @@ jobs:
   unit_tests:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
       - uses: dtolnay/rust-toolchain@nightly
       - name: Install cargo-llvm-cov
         uses: taiki-e/install-action@cargo-llvm-cov
@@ -20,7 +20,7 @@ jobs:
   integration_tests:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
       - uses: dtolnay/rust-toolchain@nightly
       - name: Install cargo-llvm-cov
         uses: taiki-e/install-action@cargo-llvm-cov

.github/workflows/format.yml

@@ -6,7 +6,7 @@ jobs:
     env:
       CARGO_UNSTABLE_SPARSE_REGISTRY: true
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
       - uses: dtolnay/rust-toolchain@nightly
         with:
           components: rustfmt

.github/workflows/fuzzing.yml

@@ -7,7 +7,7 @@ jobs:
       RUSTFLAGS: "-D warnings"
       CARGO_UNSTABLE_SPARSE_REGISTRY: true
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
       - uses: dtolnay/rust-toolchain@nightly
       - name: Install cargo fuzz
         run: cargo install cargo-fuzz --verbose

.github/workflows/lints.yml

@@ -7,7 +7,7 @@ jobs:
       RUSTFLAGS: "-D warnings"
       CARGO_UNSTABLE_SPARSE_REGISTRY: true
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
       - uses: dtolnay/rust-toolchain@stable
         with:
           components: clippy

.github/workflows/rustdoc.yml

@@ -7,7 +7,7 @@ jobs:
       RUSTDOCFLAGS: "-D warnings"
       CARGO_UNSTABLE_SPARSE_REGISTRY: true
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
       - uses: dtolnay/rust-toolchain@nightly
 
       - name: Check Rust documentation

.github/workflows/tests.yml

@@ -18,7 +18,7 @@ jobs:
       RUSTFLAGS: "-D warnings"
       CARGO_UNSTABLE_SPARSE_REGISTRY: true
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
       - uses: dtolnay/rust-toolchain@master
         with:
           toolchain: ${{ matrix.rust }}