[windows] remove unsupported platform (#3878)

README.md

@@ -1,6 +1,5 @@
 [![OpenThread][ot-logo]][ot-repo]
 [![Build Status][ot-travis-svg]][ot-travis]
-[![Build Status][ot-appveyor-svg]][ot-appveyor]
 [![Coverage Status][ot-codecov-svg]][ot-codecov]
 [![Build Status][ot-docker-dev-svg]][ot-docker-dev]
 
@@ -26,8 +25,6 @@ More information about Thread can be found at [threadgroup.org](http://threadgro
 [ot-logo]: doc/images/openthread_logo.png
 [ot-travis]: https://travis-ci.org/openthread/openthread
 [ot-travis-svg]: https://travis-ci.org/openthread/openthread.svg?branch=master
-[ot-appveyor]: https://ci.appveyor.com/project/jwhui/openthread
-[ot-appveyor-svg]: https://ci.appveyor.com/api/projects/status/r5qwyhn9p26nmfk3?svg=true
 [ot-codecov]: https://codecov.io/gh/openthread/openthread
 [ot-codecov-svg]: https://codecov.io/gh/openthread/openthread/branch/master/graph/badge.svg
 [ot-docker-dev]: https://hub.docker.com/r/openthread/environment
@@ -35,7 +32,7 @@ More information about Thread can be found at [threadgroup.org](http://threadgro
 
 # Who supports OpenThread?
 
-<a href="https://www.arm.com/"><img src="doc/images/ot-contrib-arm.png" alt="ARM" width="200px"></a><a href="https://www.cascoda.com/"><img src="doc/images/ot-contrib-cascoda.png" alt="Cascoda" width="200px"></a><a href="https://www.google.com/"><img src="doc/images/ot-contrib-google.png" alt="Google" width="200px"></a><a href="https://www.microsoft.com/en-us/"><img src="doc/images/ot-contrib-ms.png" alt="Microsoft" width="200px"></a><a href="http://www.nordicsemi.com/"><img src="doc/images/ot-contrib-nordic.png" alt="Nordic" width="200px"></a><a href="http://www.nxp.com/"><img src="doc/images/ot-contrib-nxp.png" alt="NXP" width="200px"></a><a href="https://www.particle.io/"><img src="doc/images/ot-contrib-particle.png" alt="Particle" width="200px"></a><a href="http://www.qorvo.com/"><img src="doc/images/ot-contrib-qorvo.png" alt="Qorvo" width="200px"></a><a href="https://www.qualcomm.com/"><img src="doc/images/ot-contrib-qc.png" alt="Qualcomm" width="200px"></a><a href="https://www.st.com/"><img src="doc/images/ot-contrib-stm.png" alt="STMicroelectronics" width="200px"></a><a href="https://www.synopsys.com/"><img src="doc/images/ot-contrib-synopsys.png" alt="Synopsys" width="200px"></a><a href="https://www.ti.com/"><img src="doc/images/ot-contrib-ti.png" alt="Texas Instruments" width="200px"></a><a href="https://www.zephyrproject.org/"><img src="doc/images/ot-contrib-zephyr.png" alt="Zephyr Project" width="200px"></a>
+<a href="https://www.arm.com/"><img src="doc/images/ot-contrib-arm.png" alt="ARM" width="200px"></a><a href="https://www.cascoda.com/"><img src="doc/images/ot-contrib-cascoda.png" alt="Cascoda" width="200px"></a><a href="https://www.google.com/"><img src="doc/images/ot-contrib-google.png" alt="Google" width="200px"></a><a href="http://www.nordicsemi.com/"><img src="doc/images/ot-contrib-nordic.png" alt="Nordic" width="200px"></a><a href="http://www.nxp.com/"><img src="doc/images/ot-contrib-nxp.png" alt="NXP" width="200px"></a><a href="https://www.particle.io/"><img src="doc/images/ot-contrib-particle.png" alt="Particle" width="200px"></a><a href="http://www.qorvo.com/"><img src="doc/images/ot-contrib-qorvo.png" alt="Qorvo" width="200px"></a><a href="https://www.qualcomm.com/"><img src="doc/images/ot-contrib-qc.png" alt="Qualcomm" width="200px"></a><a href="https://www.st.com/"><img src="doc/images/ot-contrib-stm.png" alt="STMicroelectronics" width="200px"></a><a href="https://www.synopsys.com/"><img src="doc/images/ot-contrib-synopsys.png" alt="Synopsys" width="200px"></a><a href="https://www.ti.com/"><img src="doc/images/ot-contrib-ti.png" alt="Texas Instruments" width="200px"></a><a href="https://www.zephyrproject.org/"><img src="doc/images/ot-contrib-zephyr.png" alt="Zephyr Project" width="200px"></a>
 
 # Getting started