Bump actions/checkout from 1 to 4

Bumps [actions/checkout](https://github.com/actions/checkout) from 1 to 4.
- [Release notes](https://github.com/actions/checkout/releases)
- [Changelog](https://github.com/actions/checkout/blob/main/CHANGELOG.md)
- [Commits](actions/checkout@v1...v4)

---
updated-dependencies:
- dependency-name: actions/checkout
  dependency-version: '4'
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

.github/workflows/CI.yml

@@ -44,7 +44,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - uses: julia-actions/setup-julia@latest
-      - uses: actions/checkout@v1
+      - uses: actions/checkout@v4
       - name: Install JuliaFormatter and format
         run: |
           julia --color=yes -e 'using Pkg; Pkg.add(PackageSpec(name="JuliaFormatter"))'

.github/workflows/deploy.yml

@@ -7,7 +7,7 @@ jobs:
   aggregate:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v4
       - uses: julia-actions/setup-julia@v1
         with:
           version: '1.8'