build(deps): bump actions/upload-artifact from 5 to 6

Bumps [actions/upload-artifact](https://github.com/actions/upload-artifact) from 5 to 6.
- [Release notes](https://github.com/actions/upload-artifact/releases)
- [Commits](https://github.com/actions/upload-artifact/compare/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>

.github/workflows/build.yml

@@ -106,7 +106,7 @@ jobs:
         run: tar zcf sources.tar.gz sources
 
       - name: Archive Source Bundle
-        uses: actions/upload-artifact@v5
+        uses: actions/upload-artifact@v6
         with:
           name: source-bundle
           path: sources.tar.gz
@@ -197,7 +197,7 @@ jobs:
         if: always()
         run: df -h
 
-      - uses: actions/upload-artifact@v5
+      - uses: actions/upload-artifact@v6
         if: ${{ always() }}
         with:
           name: linux-${{matrix.boards}}-builds
@@ -242,7 +242,7 @@ jobs:
             cd sources/nuttx
             ./tools/ci/cibuild-oot.sh
 
-      - uses: actions/upload-artifact@v5
+      - uses: actions/upload-artifact@v6
         if: ${{ always() }}
         with:
           name: oot-build-artifacts
@@ -303,7 +303,7 @@ jobs:
           cd sources/nuttx/tools/ci
           ./cibuild.sh -i -c -A -R testlist/${{matrix.boards}}.dat
 
-      - uses: actions/upload-artifact@v5
+      - uses: actions/upload-artifact@v6
         with:
           name: macos-${{matrix.boards}}-builds
           path: buildartifacts/
@@ -386,7 +386,7 @@ jobs:
           cd sources/nuttx/tools/ci
           ./cibuild.sh -g -i -A -C -N -R testlist/${{matrix.boards}}.dat
 
-      - uses: actions/upload-artifact@v5
+      - uses: actions/upload-artifact@v6
         with:
           name: msys2-${{matrix.boards}}-builds
           path: buildartifacts/
@@ -438,7 +438,7 @@ jobs:
           cd sources\nuttx\tools\ci
           .\cibuild.ps1 -n -i -A -C -N testlist\windows.dat
 
-      - uses: actions/upload-artifact@v5
+      - uses: actions/upload-artifact@v6
         with:
           name: msvc-builds
           path: ./sources/buildartifacts/