Bump actions/download-artifact from 6 to 7

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

---
updated-dependencies:
- dependency-name: actions/download-artifact
  dependency-version: '7'
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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

.github/workflows/build.yml

@@ -147,7 +147,7 @@ jobs:
       run: git submodule update --init pspautotests assets/lang
 
     - name: Download build
-      uses: actions/download-artifact@v6
+      uses: actions/download-artifact@v7
       with:
         name: Windows x64 build
         path: ppsspp/
@@ -433,7 +433,7 @@ jobs:
         git submodule update --init SDL/macOS
 
     - name: Download build
-      uses: actions/download-artifact@v6
+      uses: actions/download-artifact@v7
       with:
         name: ${{ matrix.os }} build
         path: ppsspp/