chore(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

@@ -112,7 +112,7 @@ jobs:
           tar -cf $GITHUB_WORKSPACE/qemu.tar *
 
       - name: Store QEMU
-        uses: actions/upload-artifact@v5
+        uses: actions/upload-artifact@v6
         with:
           name: qemu
           path: qemu.tar
@@ -298,7 +298,7 @@ jobs:
           tar -cf apidocs.tar apidocs
 
       - name: Store the API docs
-        uses: actions/upload-artifact@v5
+        uses: actions/upload-artifact@v6
         with:
           name: apidocs
           path: apidocs.tar
@@ -354,7 +354,7 @@ jobs:
           tar -cf book.tar bookroot
 
       - name: Store the Book + API docs
-        uses: actions/upload-artifact@v5
+        uses: actions/upload-artifact@v6
         with:
           name: book
           path: book.tar
@@ -430,7 +430,7 @@ jobs:
           tar -cf mdbookold.tar mdbookold
 
       - name: Store the old API docs
-        uses: actions/upload-artifact@v5
+        uses: actions/upload-artifact@v6
         with:
           name: mdbookold
           path: mdbookold.tar
@@ -613,7 +613,7 @@ jobs:
           tar -cf bookstodeploy.tar bookstodeploy
 
       - name: Store the books
-        uses: actions/upload-artifact@v5
+        uses: actions/upload-artifact@v6
         with:
           name: bookstodeploy
           path: bookstodeploy.tar