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/ci.yml

@@ -31,7 +31,7 @@ jobs:
           - {VERSION: "3.9", TOXENV: "py39", OPENSSL: {TYPE: "libressl", VERSION: "3.2.2"}}
     name: "${{ matrix.PYTHON.TOXENV }} ${{ matrix.PYTHON.OPENSSL.TYPE }} ${{ matrix.PYTHON.OPENSSL.VERSION }} ${{ matrix.PYTHON.OPENSSL.CONFIG_FLAGS }}"
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v4
       - name: Setup python
         uses: actions/setup-python@v2
         with:
@@ -102,7 +102,7 @@ jobs:
           - {IMAGE: "pyca/cryptography-runner-alpine", TOXENV: "py38"}
     name: "tox -e ${{ matrix.IMAGE.TOXENV }} on ${{ matrix.IMAGE.IMAGE }} ${{ matrix.IMAGE.ENV }}"
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v4
       - run: 'git clone --depth=1 https://github.com/google/wycheproof "$HOME/wycheproof"'
       - run: 'echo "$ENV_VAR" >> $GITHUB_ENV'
         if: matrix.IMAGE.ENV
@@ -125,7 +125,7 @@ jobs:
           - {VERSION: "3.9", TOXENV: "py39", EXTRA_CFLAGS: "-DUSE_OSRANDOM_RNG_FOR_TESTING"}
     name: "Python ${{ matrix.PYTHON.VERSION }} on macOS"
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v4
       - name: Setup python
         uses: actions/setup-python@v2
         with:
@@ -169,7 +169,7 @@ jobs:
           - {VERSION: "3.9", TOXENV: "py39", MSVC_VERSION: "2019", CL_FLAGS: "/D USE_OSRANDOM_RNG_FOR_TESTING"}
     name: "Python ${{ matrix.PYTHON.VERSION }} on ${{ matrix.WINDOWS.WINDOWS }}"
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v4
       - name: Setup python
         uses: actions/setup-python@v2
         with:
@@ -217,7 +217,7 @@ jobs:
           - certbot-josepy
     name: "Downstream tests for ${{ matrix.DOWNSTREAM }}"
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v4
       - name: Setup python
         uses: actions/setup-python@v2
         with:
@@ -233,7 +233,7 @@ jobs:
     runs-on: ubuntu-latest
     name: "linkcheck"
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v4
       - name: Setup python
         uses: actions/setup-python@v2
         with:

.github/workflows/wheel-builder.yml

@@ -67,7 +67,7 @@ jobs:
             BIN_PATH: '/Library/Frameworks/Python.framework/Versions/3.8/bin/python3'
     name: "${{ matrix.PYTHON.VERSION }} ABI ${{ matrix.PYTHON.ABI_VERSION }} macOS"
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v4
       - run: |
           curl "$PYTHON_DOWNLOAD_URL" -o python.pkg
           sudo installer -pkg python.pkg -target /
@@ -118,7 +118,7 @@ jobs:
           - {VERSION: "3.8", MSVC_VERSION: "2019", "USE_ABI3": "true", "ABI_VERSION": "cp36"}
     name: "${{ matrix.PYTHON.VERSION }} ${{ matrix.WINDOWS.WINDOWS }} ${{ matrix.PYTHON.ABI_VERSION }}"
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v4
       - name: Setup python
         uses: actions/setup-python@v2
         with: