DOC: Readme: Add SLOC badge

Author: kernc

README.md

@@ -1,9 +1,10 @@
 [![SAMBO - Sequential And Model-Based Optimization](logo.svg)](https://sambo-optimization.github.io/)
 =====
 [![Build Status](https://img.shields.io/github/actions/workflow/status/sambo-optimization/sambo/ci.yml?branch=master&style=for-the-badge)](https://github.com/sambo-optimization/sambo/actions)
-[![Code Coverage](https://img.shields.io/badge/coverage-96%25-%2397ca00?style=for-the-badge)](https://github.com/sambo-optimization/sambo/actions/workflows/ci.yml)
+[![Code Coverage](https://img.shields.io/badge/coverage-96%25-%2397ca00?style=for-the-badge&label=Covr)](https://github.com/sambo-optimization/sambo/actions/workflows/ci.yml)
+[![Source lines of code](https://img.shields.io/endpoint?url=https%3A%2F%2Fghloc.vercel.app%2Fapi%2Fsambo-optimization%2Fsambo%2Fbadge?filter=.py%26format=human&style=for-the-badge&label=SLOC&color=green)](https://ghloc.vercel.app/sambo-optimization/sambo)
 [![sambo on PyPI](https://img.shields.io/pypi/v/sambo.svg?color=blue&style=for-the-badge)](https://pypi.org/project/sambo)
-[![package downloads](https://img.shields.io/pypi/dm/sambo.svg?color=skyblue&style=for-the-badge)](https://pypistats.org/packages/sambo)
+[![package downloads](https://img.shields.io/pypi/dm/sambo.svg?style=for-the-badge&color=skyblue&label=D/L)](https://pypistats.org/packages/sambo)
 [![total downloads](https://img.shields.io/pepy/dt/sambo?style=for-the-badge&label=%E2%88%91&color=skyblue)](https://pypistats.org/packages/sambo)
 [![GitHub Sponsors](https://img.shields.io/github/sponsors/kernc?color=pink&style=for-the-badge&label=%E2%99%A5)](https://github.com/sponsors/kernc)