Bump actions/upload-artifact from 5 to 6 (#3985)

Bumps [actions/upload-artifact](https://github.com/actions/upload-artifact) from 5 to 6.
- [Release notes](https://github.com/actions/upload-artifact/releases)
- [Commits](actions/upload-artifact@v5...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>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

.github/workflows/build_artifacts.yml

@@ -51,7 +51,7 @@ jobs:
 
             - name: Upload Screenshots
               if: ${{ always() }}
-              uses: actions/upload-artifact@v5
+              uses: actions/upload-artifact@v6
               with:
                   name: Screenshots-${{ github.run_number }}
                   path: ${{ github.workspace }}\tests\MaterialDesignThemes.UITests\bin\${{ inputs.build-configuration }}\net9.0-windows\Screenshots
@@ -61,13 +61,13 @@ jobs:
               run: .\build\BuildNugets.ps1 -MDIXVersion ${{ inputs.mdix-version }} -MDIXColorsVersion ${{ inputs.mdix-colors-version }} -MDIXMahAppsVersion ${{ inputs.mdix-mahapps-version }}
 
             - name: Upload NuGets
-              uses: actions/upload-artifact@v5
+              uses: actions/upload-artifact@v6
               with:
                   name: NuGets
                   path: "*.nupkg"
 
             - name: Upload Demo App
-              uses: actions/upload-artifact@v5
+              uses: actions/upload-artifact@v6
               with:
                   name: DemoApp
                   path: "src/MainDemo.Wpf/bin/${{ env.buildConfiguration }}"

.github/workflows/release.yml

@@ -65,7 +65,7 @@ jobs:
                   cat "ReleaseNotes.md"
 
             - name: Upload Release Notes
-              uses: actions/upload-artifact@v5
+              uses: actions/upload-artifact@v6
               with:
                   name: ReleaseNotes
                   path: "ReleaseNotes.md"
@@ -106,7 +106,7 @@ jobs:
                   dotnet run --project ./src/MaterialDesignToolkit.ResourceGeneration/MaterialDesignToolkit.ResourceGeneration.csproj -c Release -- icon-diff
 
             - name: Upload Icon Changes
-              uses: actions/upload-artifact@v5
+              uses: actions/upload-artifact@v6
               with:
                   name: IconChanges
                   path: "IconChanges*.md"