Bump actions/download-artifact from 4 to 5

Bumps [actions/download-artifact](https://github.com/actions/download-artifact) from 4 to 5.
- [Release notes](https://github.com/actions/download-artifact/releases)
- [Commits](actions/download-artifact@v4...v5)

---
updated-dependencies:
- dependency-name: actions/download-artifact
  dependency-version: '5'
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

.github/workflows/coverage.yml

@@ -68,7 +68,7 @@ jobs:
           submodules: true
       - run: sudo apt-get update
       - run: sudo apt-get install lcov
-      - uses: actions/download-artifact@v4
+      - uses: actions/download-artifact@v5
         with:
           pattern: coverage-*
           path: build/

.github/workflows/publish.yml

@@ -34,7 +34,7 @@ jobs:
     permissions:
       id-token: write
     steps:
-    - uses: actions/download-artifact@v4
+    - uses: actions/download-artifact@v5
       with:
         pattern: python-gmp-*
         path: dist/
@@ -51,7 +51,7 @@ jobs:
       contents: write
       id-token: write
     steps:
-    - uses: actions/download-artifact@v4
+    - uses: actions/download-artifact@v5
       with:
         pattern: python-gmp-*
         path: dist/