chore: remove lgtm badges

https://github.blog/news-insights/product-news/the-next-step-for-lgtm-com-github-code-scanning/

README.md

@@ -3,8 +3,6 @@
 [![build (qemu)](https://github.com/nabaztag2018/pynab/actions/workflows/arm-runner.yml/badge.svg?branch=master)](https://github.com/nabaztag2018/pynab/actions/workflows/arm-runner.yml)
 [![tests](https://github.com/nabaztag2018/pynab/actions/workflows/tests.yml/badge.svg?branch=master)](https://github.com/nabaztag2018/pynab/actions/workflows/tests.yml)
 [![Code style: black](https://img.shields.io/badge/code%20style-black-000000.svg)](https://github.com/psf/black)
-[![Total alerts](https://img.shields.io/lgtm/alerts/g/nabaztag2018/pynab.svg?logo=lgtm&logoWidth=18)](https://lgtm.com/projects/g/nabaztag2018/pynab/alerts/)
-[![Language grade: Python](https://img.shields.io/lgtm/grade/python/g/nabaztag2018/pynab.svg?logo=lgtm&logoWidth=18)](https://lgtm.com/projects/g/nabaztag2018/pynab/context:python)
 [![codecov](https://codecov.io/gh/nabaztag2018/pynab/branch/master/graph/badge.svg)](https://codecov.io/gh/nabaztag2018/pynab)
 [![Twitter](https://img.shields.io/twitter/follow/nabaztagtagtag?label=Follow&style=social)](https://twitter.com/nabaztagtagtag)