[skip ci] Remove MinGW build status from README

don't think we'll ever re-activate that one. for reference: only fedora:rawhide is somewhat set up to build mingw for geospatial stuff and there's only one maintainer for most geospatial packages, plus rawhide regularly breaks as it's cutting edge without much testing

README.md

@@ -18,9 +18,9 @@ Valhalla is an open source routing engine and accompanying libraries for use wit
 
 ## Build Status
 
-| Linux/MacOs | Windows | MinGW64 | Code Coverage |
-| ----------- | ------- | ------------- | ------------- |
-| [![Circle CI](https://circleci.com/gh/valhalla/valhalla/tree/master.svg?style=svg)](https://circleci.com/gh/valhalla/valhalla/tree/master) | [![Build Status](https://dev.azure.com/valhalla1/valhalla/_apis/build/status/valhalla.valhalla?branchName=master)](https://dev.azure.com/valhalla1/valhalla/_build/latest?definitionId=1&branchName=master) | ![Valhalla MinGW Build](https://github.com/valhalla/valhalla/workflows/Valhalla%20MinGW%20Build/badge.svg) | [![codecov](https://codecov.io/gh/valhalla/valhalla/branch/master/graph/badge.svg)](https://codecov.io/gh/valhalla/valhalla) |
+| Linux/MacOs | Windows | Code Coverage |
+| ----------- | ------- | ------------- |
+| [![Circle CI](https://circleci.com/gh/valhalla/valhalla/tree/master.svg?style=svg)](https://circleci.com/gh/valhalla/valhalla/tree/master) | [![Build Status](https://dev.azure.com/valhalla1/valhalla/_apis/build/status/valhalla.valhalla?branchName=master)](https://dev.azure.com/valhalla1/valhalla/_build/latest?definitionId=1&branchName=master) | [![codecov](https://codecov.io/gh/valhalla/valhalla/branch/master/graph/badge.svg)](https://codecov.io/gh/valhalla/valhalla) |
 
 
 ## License