Build(deps): Bump actions/download-artifact from 5 to 6

Bumps [actions/download-artifact](https://github.com/actions/download-artifact) from 5 to 6.
- [Release notes](https://github.com/actions/download-artifact/releases)
- [Commits](actions/download-artifact@v5...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] <[email protected]>

Author: dependabot[bot]

.github/workflows/main.yml

@@ -135,7 +135,7 @@ jobs:
         set -xe
         python -m pip install --upgrade coverage[toml]
     - name: Download coverage data for all test runs
-      uses: actions/download-artifact@v5
+      uses: actions/download-artifact@v6
       with:
         pattern: coverage-*
         path: coverage
@@ -195,7 +195,7 @@ jobs:
         name: release-notes.md
         path: release-notes.md
     - name: Download distributions
-      uses: actions/download-artifact@v5
+      uses: actions/download-artifact@v6
       with:
         name: dist
         path: dist
@@ -221,7 +221,7 @@ jobs:
       id-token: write
     steps:
     - name: Download distributions
-      uses: actions/download-artifact@v5
+      uses: actions/download-artifact@v6
       with:
         name: dist
         path: dist
@@ -240,7 +240,7 @@ jobs:
       id-token: write
     steps:
     - name: Download distributions
-      uses: actions/download-artifact@v5
+      uses: actions/download-artifact@v6
       with:
         name: dist
         path: dist