message: Add Web build badge
diff: <img alt="Linux" src="build/img/linux.png" width="20px" height="20px" hspace="2px"/>[![Linux Build Status](https://filament-build.storage.googleapis.com/badges/build_status_linux.svg)](https://filament-build.storage.googleapis.com/badges/build_link_linux.html)
  <img alt="macOS" src="build/img/macos.png" width="20px" height="20px" hspace="2px"/>[![MacOS Build Status](https://filament-build.storage.googleapis.com/badges/build_status_mac.svg)](https://filament-build.storage.googleapis.com/badges/build_link_mac.html)
  <img alt="Windows" src="build/img/windows.png" width="20px" height="20px" hspace="2px"/>[![Windows Build Status](https://filament-build.storage.googleapis.com/badges/build_status_windows.svg)](https://filament-build.storage.googleapis.com/badges/build_link_windows.html)
  +<img alt="Web" src="build/img/windows.png" width="20px" height="20px" hspace="2px"/>[![Web Build Status](https://filament-build.storage.googleapis.com/badges/build_status_web.svg)](https://filament-build.storage.googleapis.com/badges/build_link_web.html)
  Filament is a real-time physically based rendering engine for Android, Linux, macOS and Windows.
  This rendering engine was designed to be as small as possible and as efficient as possible
  