[docs] Update badge for Link checks workflow (#6568)

Update badge for Link checks workflow

README.md

@@ -10,7 +10,7 @@ Light Gradient Boosting Machine
 [![Azure Pipelines Build Status](https://lightgbm-ci.visualstudio.com/lightgbm-ci/_apis/build/status/Microsoft.LightGBM?branchName=master)](https://lightgbm-ci.visualstudio.com/lightgbm-ci/_build/latest?definitionId=1)
 [![Appveyor Build Status](https://ci.appveyor.com/api/projects/status/1ys5ot401m0fep6l/branch/master?svg=true)](https://ci.appveyor.com/project/guolinke/lightgbm/branch/master)
 [![Documentation Status](https://readthedocs.org/projects/lightgbm/badge/?version=latest)](https://lightgbm.readthedocs.io/)
-[![Link checks](https://github.com/microsoft/LightGBM/workflows/Link%20checks/badge.svg)](https://github.com/microsoft/LightGBM/actions?query=workflow%3A%22Link+checks%22)
+[![Link checks](https://github.com/microsoft/LightGBM/actions/workflows/linkchecker.yml/badge.svg?branch=master)](https://github.com/microsoft/LightGBM/actions/workflows/linkchecker.yml)
 [![License](https://img.shields.io/github/license/microsoft/lightgbm.svg)](https://github.com/microsoft/LightGBM/blob/master/LICENSE)
 [![Python Versions](https://img.shields.io/pypi/pyversions/lightgbm.svg?logo=python&logoColor=white)](https://pypi.org/project/lightgbm)
 [![PyPI Version](https://img.shields.io/pypi/v/lightgbm.svg?logo=pypi&logoColor=white)](https://pypi.org/project/lightgbm)