Bump actions/download-artifact from 7 to 8

Bumps [actions/download-artifact](https://github.com/actions/download-artifact) from 7 to 8.
- [Release notes](https://github.com/actions/download-artifact/releases)
- [Commits](actions/download-artifact@v7...v8)

---
updated-dependencies:
- dependency-name: actions/download-artifact
  dependency-version: '8'
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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

Author: dependabot[bot]

.github/workflows/build-nuget.yml

@@ -46,31 +46,31 @@ jobs:
                 fi
 
             - name: Download artifacts - SDL2-CS.dll
-              uses: actions/download-artifact@v7
+              uses: actions/download-artifact@v8
               with:
                 name: SDL2-CS
                 path: ./bin
 
             - name: Download artifacts - native - Windows
-              uses: actions/download-artifact@v7
+              uses: actions/download-artifact@v8
               with:
                 name: Natives-Windows
                 path: ./native/win
 
             - name: Download artifacts - native - MacOS
-              uses: actions/download-artifact@v7
+              uses: actions/download-artifact@v8
               with:
                 name: Natives-MacOS
                 path: ./native/osx
 
             - name: Download artifacts - native - Linux (x64)
-              uses: actions/download-artifact@v7
+              uses: actions/download-artifact@v8
               with:
                 name: Natives-Linux(x64)
                 path: ./native/linux
 
             - name: Download artifacts - native - Linux (arm64)
-              uses: actions/download-artifact@v7
+              uses: actions/download-artifact@v8
               with:
                 name: Natives-Linux(arm64)
                 path: ./native/linux