Bump actions/checkout from 3 to 4

Bumps [actions/checkout](https://github.com/actions/checkout) from 3 to 4.
- [Release notes](https://github.com/actions/checkout/releases)
- [Changelog](https://github.com/actions/checkout/blob/main/CHANGELOG.md)
- [Commits](actions/checkout@v3...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>

Author: dependabot[bot]

.github/workflows/codeql-analysis.yml

@@ -29,7 +29,7 @@ jobs:
 
     steps:
     - name: Checkout repository
-      uses: actions/checkout@v3
+      uses: actions/checkout@v4
 
     - name: Install dotnet
       uses: actions/setup-dotnet@v3

.github/workflows/emacs-test.yml

@@ -17,7 +17,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Checkout repository
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
 
       - name: Install dotnet
         uses: actions/setup-dotnet@v3

.github/workflows/vim-test.yml

@@ -17,7 +17,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Checkout repository
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
 
       - name: Install dotnet
         uses: actions/setup-dotnet@v3
@@ -31,13 +31,13 @@ jobs:
         id: vim
 
       - name: Checkout vim-ps1
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
         with:
           repository: PProvost/vim-ps1
           path: vim-ps1
 
       - name: Checkout LanguageClient-neovim
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
         with:
           repository: autozimu/LanguageClient-neovim
           path: LanguageClient-neovim
@@ -47,7 +47,7 @@ jobs:
         working-directory: LanguageClient-neovim
 
       - name: Checkout Themis
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
         with:
           repository: thinca/vim-themis
           path: vim-themis