build(deps): 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] <[email protected]>

.github/workflows/go.yml

@@ -19,7 +19,7 @@ jobs:
         go-version: ^1.16
 
     - name: Check out code
-      uses: actions/checkout@v2
+      uses: actions/checkout@v4
 
     - name: Build
       run: go build -v ./...

.github/workflows/gofmt.yml

@@ -14,7 +14,7 @@ jobs:
     steps:
 
     - name: Check out code
-      uses: actions/checkout@v2
+      uses: actions/checkout@v4
 
     - name: Check gofmt
       uses: Jerome1337/[email protected]

.github/workflows/psl-update.yml

@@ -11,7 +11,7 @@ jobs:
     steps:
 
       - name: Check out code
-        uses: actions/checkout@v2
+        uses: actions/checkout@v4
 
       - name: Set up Go
         uses: actions/setup-go@v2