Upgrade CI actions to latest versions

Updated CI workflow to use newer action versions.

Author: amontoison

.github/workflows/ci.yml

@@ -39,12 +39,12 @@ jobs:
             arch: x64
             allow_failure: true
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
       - uses: julia-actions/setup-julia@v2
         with:
           version: ${{ matrix.version }}
           arch: ${{ matrix.arch }}
-      - uses: actions/cache@v3
+      - uses: actions/cache@v4
         env:
           cache-name: cache-artifacts
         with:
@@ -57,7 +57,8 @@ jobs:
       - uses: julia-actions/julia-buildpkg@v1
       - uses: julia-actions/julia-runtest@v1
       - uses: julia-actions/julia-processcoverage@v1
-      - uses: codecov/codecov-action@v3
+      - uses: codecov/codecov-action@v4
         with:
           files: lcov.info
 
+