do not fail CI if codecov upload fails

Author: timvink

.github/workflows/unittests_codecov.yml

@@ -69,4 +69,4 @@ jobs:
         token: ${{ secrets.CODECOV_TOKEN }}
         file: ./coverage.xml
         flags: unittests
-        fail_ci_if_error: true
+        fail_ci_if_error: false