Bump actions/upload-artifact from 3 to 4

Bumps [actions/upload-artifact](https://github.com/actions/upload-artifact) from 3 to 4.
- [Release notes](https://github.com/actions/upload-artifact/releases)
- [Commits](actions/upload-artifact@v3...v4)

---
updated-dependencies:
- dependency-name: actions/upload-artifact
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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

.github/workflows/benchmark.yml

@@ -45,7 +45,7 @@ jobs:
         run: julia --project=benchmark/ -e 'using Pkg; Pkg.develop(PackageSpec(path=pwd())); Pkg.instantiate()'
       - name: Run benchmarks
         run: julia --project=benchmark/ --color=yes benchmark/run_benchmarks.jl
-      - uses: actions/upload-artifact@v3
+      - uses: actions/upload-artifact@v4
         with:
           name: my-artifact
           path: benchmark/results*.md

.github/workflows/ci.yml

@@ -153,7 +153,7 @@ jobs:
       - shell: bash
         run: |
           cp ./lcov.info ./lcov-${{ matrix.trixi_test }}-${{ matrix.os }}-${{ matrix.version }}-${{ matrix.arch }}.info
-      - uses: actions/upload-artifact@v3
+      - uses: actions/upload-artifact@v4
         with:
           name: lcov-${{ matrix.trixi_test }}-${{ matrix.os }}-${{ matrix.version }}-${{ matrix.arch }}
           path: ./lcov-${{ matrix.trixi_test }}-${{ matrix.os }}-${{ matrix.version }}-${{ matrix.arch }}.info
@@ -199,7 +199,7 @@ jobs:
           github-token: ${{ secrets.GITHUB_TOKEN }}
           path-to-lcov: ./lcov.info
       # Upload merged coverage data as artifact for debugging
-      - uses: actions/upload-artifact@v3
+      - uses: actions/upload-artifact@v4
         with:
           name: lcov
           path: ./lcov.info