[CI] Use actions/checkout@v4 (#80)

If v3 is used , attempts to use sapling on macos-latest (aka M1 running MacOS Sonoma) will fail with cryptic
```
abort: cannot initialize working copy: When constructing alloc::boxed::Box<dyn commits_trait::DagCommits + core::marker::Send> from dyn storemodel::StoreInfo, "10-git-commits" reported error: resolving a4d6b74 to git commit: object not found - no match for id (a4d6b74); class=Odb (9); code=NotFound (-3)
```

.github/workflows/CI.yml

@@ -30,7 +30,7 @@ jobs:
 
     runs-on: ${{ matrix.os }}
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
       - uses: actions-rs/toolchain@v1
         with:
           toolchain: stable
@@ -61,7 +61,7 @@ jobs:
       matrix:
         target: [x86_64, aarch64]
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
       - name: Build wheels
         uses: PyO3/maturin-action@v1
         with:
@@ -82,7 +82,7 @@ jobs:
       matrix:
         target: [x86, x86_64]
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
       - name: Build wheels
         uses: PyO3/maturin-action@v1
         with:
@@ -102,7 +102,7 @@ jobs:
       matrix:
         target: [x86_64, aarch64]
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
       - name: Build wheels
         uses: PyO3/maturin-action@v1
         with:
@@ -119,7 +119,7 @@ jobs:
     runs-on: ubuntu-latest
     needs: test
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
       - name: Build sdist
         uses: PyO3/maturin-action@v1
         with: