github: update actions/upload-artifact to v4

As described in the blog post below, we need to migrate to
actions/upload-artifact@v4.

https://github.blog/changelog/2024-04-16-deprecation-notice-v3-of-the-artifact-actions

Signed-off-by: Paul Moore <[email protected]>

Author: pcmoore

.github/workflows/continuous-integration.yml

@@ -98,7 +98,7 @@ jobs:
         flag-name: "amd64"
     - name: Archive code coverage results
       if: ${{ always() }}
-      uses: actions/upload-artifact@v3
+      uses: actions/upload-artifact@v4
       with:
         name: Code Coverage Artifacts
         path: |