Merge pull request #102 from WIAS-PDELib/jf/fix-buildstatusbadge

fix build status badge

Author: j-fu

README.md

@@ -1,6 +1,6 @@
 # Extendable grid data container for numerical simulations
 
-[![Build status](https://github.com/WIAS-PDELib/ExtendableGrids.jl/workflows/linux-macos-windows/badge.svg)](https://github.com/WIAS-PDELib/ExtendableGrids.jl/actions)
+[![Build status](https://github.com/WIAS-PDELib/ExtendableGrids.jl/actions/workflows/ci.yml/badge.svg?branch=master)](https://github.com/WIAS-PDELib/ExtendableGrids.jl/actions/workflows/ci.yml?query=branch%3Amaster)
 [![](https://img.shields.io/badge/docs-stable-blue.svg)](https://WIAS-PDELib.github.io/ExtendableGrids.jl/stable)
 [![](https://img.shields.io/badge/docs-dev-blue.svg)](https://WIAS-PDELib.github.io/ExtendableGrids.jl/dev)
 [![code style: runic](https://img.shields.io/badge/code_style-%E1%9A%B1%E1%9A%A2%E1%9A%BE%E1%9B%81%E1%9A%B2-black)](https://github.com/fredrikekre/Runic.jl)