Upgrade apk before downloading lcov

There was an error to retrieve lcov in CI. By just upgrading apk before
the download operation, we ensure that we have the latest and greatest
without the need of regenerating the base image.

.github/workflows/ci.yml

@@ -40,6 +40,7 @@ jobs:
     -
       name: Install and setup lcov base
       run: |
+          apk upgrade
           apk add lcov --update-cache --repository  http://dl-3.alpinelinux.org/alpine/edge/testing/
           lcov -i --capture --directory "./build/src/" --output-file base-coverage.info --no-external --directory "./" --exclude "*/ut/*" --exclude "*/main*"
     -