Bump actions/upload-artifact from 6 to 7 (#4014)

Bumps [actions/upload-artifact](https://github.com/actions/upload-artifact) from 6 to 7.
- [Release notes](https://github.com/actions/upload-artifact/releases)
- [Commits](actions/upload-artifact@v6...v7)

---
updated-dependencies:
- dependency-name: actions/upload-artifact
  dependency-version: '7'
  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

@@ -52,7 +52,7 @@ jobs:
 
       - name: Upload Screenshots
         if: ${{ always() }}
-        uses: actions/upload-artifact@v6
+        uses: actions/upload-artifact@v7
         with:
             name: Screenshots-${{ github.run_number }}
             path: ${{ github.workspace }}\tests\MaterialDesignThemes.UITests\bin\${{ inputs.build-configuration }}\net9.0-windows\Screenshots
@@ -62,13 +62,13 @@ 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@v6
+        uses: actions/upload-artifact@v7
         with:
             name: NuGets
             path: "*.nupkg"
 
       - name: Upload Demo App
-        uses: actions/upload-artifact@v6
+        uses: actions/upload-artifact@v7
         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@v6
+        uses: actions/upload-artifact@v7
         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@v6
+        uses: actions/upload-artifact@v7
         with:
           name: IconChanges
           path: "IconChanges*.md"