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](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>

Author: dependabot[bot]

.github/workflows/build.yml

@@ -117,7 +117,7 @@ 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
@@ -208,7 +208,7 @@ jobs:
         if: always()
         run: df -h
 
-      - uses: actions/upload-artifact@v5
+      - uses: actions/upload-artifact@v6
         if: ${{ always() }}
         with:
           name: linux-${{matrix.boards}}-builds
@@ -253,7 +253,7 @@ jobs:
             cd sources/nuttx
             ./tools/ci/cibuild-oot.sh
 
-      - uses: actions/upload-artifact@v5
+      - uses: actions/upload-artifact@v6
         if: ${{ always() }}
         with:
           name: oot-build-artifacts
@@ -314,7 +314,7 @@ jobs:
           cd sources/nuttx/tools/ci
           ./cibuild.sh -i -c -A -R testlist/${{matrix.boards}}.dat
 
-      - uses: actions/upload-artifact@v5
+      - uses: actions/upload-artifact@v6
         with:
           name: macos-${{matrix.boards}}-builds
           path: buildartifacts/
@@ -397,7 +397,7 @@ jobs:
           cd sources/nuttx/tools/ci
           ./cibuild.sh -g -i -A -C -N -R testlist/${{matrix.boards}}.dat
 
-      - uses: actions/upload-artifact@v5
+      - uses: actions/upload-artifact@v6
         with:
           name: msys2-${{matrix.boards}}-builds
           path: buildartifacts/
@@ -449,7 +449,7 @@ 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/

.github/workflows/doc.yml

@@ -45,7 +45,7 @@ jobs:
           pip3 install pipenv
           pipenv install
           pipenv run make html
-      - uses: actions/upload-artifact@v5
+      - uses: actions/upload-artifact@v6
         with:
           name: sphinx-docs
           path: |