build(deps): bump actions/download-artifact from 4 to 6

Bumps [actions/download-artifact](https://github.com/actions/download-artifact) from 4 to 6.
- [Release notes](https://github.com/actions/download-artifact/releases)
- [Commits](actions/download-artifact@v4...v6)

---
updated-dependencies:
- dependency-name: actions/download-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

@@ -48,7 +48,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Download artifacts
-        uses: actions/download-artifact@v4
+        uses: actions/download-artifact@v6
 
       - name: Install dependencies
         run: |
@@ -77,7 +77,7 @@ jobs:
         uses: actions/checkout@v4
 
       - name: Download artifacts
-        uses: actions/download-artifact@v4
+        uses: actions/download-artifact@v6
 
       - name: Build source
         run: |
@@ -100,7 +100,7 @@ jobs:
         uses: actions/checkout@v4
 
       - name: Download artifacts
-        uses: actions/download-artifact@v4
+        uses: actions/download-artifact@v6
 
       - name: Work around GitHub permissions bug
         run: chmod +x *.bin/*/shellcheck*
@@ -135,7 +135,7 @@ jobs:
         uses: actions/checkout@v4
 
       - name: Download artifacts
-        uses: actions/download-artifact@v4
+        uses: actions/download-artifact@v6
 
       - name: Upload to GitHub
         env: