build(deps): 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](https://github.com/actions/download-artifact/compare/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>

.github/workflows/buildkit.yml

@@ -73,7 +73,7 @@ jobs:
     steps:
       -
         name: Download artifacts
-        uses: actions/download-artifact@v7
+        uses: actions/download-artifact@v8
         with:
           path: /tmp/buildx-output
           name: ${{ needs.binaries.outputs.artifact-name }}
@@ -345,7 +345,7 @@ jobs:
     steps:
       -
         name: Download release binaries
-        uses: actions/download-artifact@v7
+        uses: actions/download-artifact@v8
         with:
           path: ${{ env.DESTDIR }}
           name: buildkit-release

.github/workflows/dockerd.yml

@@ -114,7 +114,7 @@ jobs:
           buildkitd-flags: --debug
       -
         name: Download dockerd
-        uses: actions/download-artifact@v7
+        uses: actions/download-artifact@v8
         with:
           name: dockerd
           path: ./build/

.github/workflows/test-os.yml

@@ -144,7 +144,7 @@ jobs:
           cache: false
       -
         name: Download artifacts
-        uses: actions/download-artifact@v7
+        uses: actions/download-artifact@v8
         with:
           name: buildkit-windows-amd64
           path: ${{ github.workspace }}\bin
@@ -211,7 +211,7 @@ jobs:
         uses: actions/checkout@v6
       -
         name: Download artifacts
-        uses: actions/download-artifact@v7
+        uses: actions/download-artifact@v8
         with:
           name: buildkit-freebsd-amd64
           path: ${{ env.DESTDIR }}