Bump actions/checkout from 3 to 4 (#337)

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>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

.github/workflows/UnitTest.yml

@@ -36,7 +36,7 @@ jobs:
             julia-arch: x86
 
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
       - name: "Set up Julia"
         uses: julia-actions/setup-julia@v1
         with:

.github/workflows/docs.yml

@@ -18,7 +18,7 @@ jobs:
         julia-version: [1]
         os: [ubuntu-latest]
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
       - uses: julia-actions/setup-julia@latest
         with:
           version: ${{ matrix.julia-version }}

.github/workflows/invalidations.yml

@@ -8,12 +8,12 @@ jobs:
     - uses: julia-actions/setup-julia@v1
       with:
         version: '1'
-    - uses: actions/checkout@v3
+    - uses: actions/checkout@v4
     - uses: julia-actions/julia-buildpkg@latest
     - uses: julia-actions/julia-invalidations@v1
       id: invs_pr
 
-    - uses: actions/checkout@v3
+    - uses: actions/checkout@v4
       with:
         ref: 'master'
     - uses: julia-actions/julia-buildpkg@latest