Bump actions/upload-artifact from 4 to 6

Bumps [actions/upload-artifact](https://github.com/actions/upload-artifact) from 4 to 6.
- [Release notes](https://github.com/actions/upload-artifact/releases)
- [Commits](actions/upload-artifact@v4...v6)

---
updated-dependencies:
- dependency-name: actions/upload-artifact
  dependency-version: '6'
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

.github/workflows/dotnet-build.yml

@@ -48,7 +48,7 @@ jobs:
       run: dotnet publish Interface/Interface.csproj -c Release --runtime ${{ matrix.runtime-identifier }} --self-contained /p:PublishSingleFile=true /p:PublishTrimmed=true -o artifacts/${{ matrix.runtime-identifier }}
 
     - name: Upload Izumi-chan-${{ github.run_number }}-${{ matrix.runtime-identifier }} artifact
-      uses: actions/upload-artifact@v4
+      uses: actions/upload-artifact@v6
       with:
         name: Izumi-chan-${{ github.run_number }}-${{ matrix.runtime-identifier }}
         path: |

.github/workflows/dotnet-desktop.yml

@@ -48,7 +48,7 @@ jobs:
       run: dotnet publish Interface/Interface.csproj -c Release --runtime ${{ matrix.runtime-identifier }} --self-contained /p:PublishSingleFile=true /p:PublishTrimmed=true -o artifacts/${{ matrix.runtime-identifier }}
 
     - name: Upload Izumi-chan-${{ github.run_number }}-${{ matrix.runtime-identifier }} artifact
-      uses: actions/upload-artifact@v4
+      uses: actions/upload-artifact@v6
       with:
         name: Izumi-chan-${{ github.run_number }}-${{ matrix.runtime-identifier }}
         path: |