Bump actions/checkout from 2 to 4

Bumps [actions/checkout](https://github.com/actions/checkout) from 2 to 4.
- [Release notes](https://github.com/actions/checkout/releases)
- [Changelog](https://github.com/actions/checkout/blob/main/CHANGELOG.md)
- [Commits](actions/checkout@v2...v4)

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

Signed-off-by: dependabot[bot] <support@github.com>

.github/workflows/build.yaml

@@ -8,7 +8,7 @@ jobs:
 
     steps:
       - name: Checkout code
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
 
       - name: setup-msys2
         uses: msys2/setup-msys2@v2

.github/workflows/cygwin.yml

@@ -15,7 +15,7 @@ jobs:
     name: Fedora cross ${{ matrix.target }}
 
     steps:
-    - uses: actions/checkout@v2
+    - uses: actions/checkout@v4
 
     # install build tools
     - run: dnf install -y autoconf automake make patch perl
@@ -60,7 +60,7 @@ jobs:
     # endings, but this could still be dangerous e.g if we need symlinks in the
     # repo)
     - run: git config --global core.autocrlf input
-    - uses: actions/checkout@v2
+    - uses: actions/checkout@v4
 
     # install cygwin and build tools
     - name: Install Cygwin