As suggested in the docs I used
travis setup releases generating the barebone configuration for pushing a release on github. However since it does not include the option
skip_cleanup: true the file I wanted to be released was not found.
deploy: provider: releases api_key: secure: blablakey file: app/build/outputs/apk/debug/app-debug.apk on: repo: lprc/simple-dl branch: travis
skip_cleanup: true should really be included since the use of it is explicitely suggested in the docs.