Update README.md

Author: xtruan

README.md

@@ -1,4 +1,7 @@
 # FlipBIP - BIP32/39/44
+
+[![Build](https://github.com/xtruan/FlipBIP/actions/workflows/build.yml/badge.svg?branch=main)](https://github.com/xtruan/FlipBIP/actions/workflows/build.yml)
+
 ## Crypto toolkit for Flipper Zero
 - Built against `0.78.1` Flipper Zero firmware release
 - Using Trezor crypto libs from `core/v2.5.3` release
@@ -71,4 +74,4 @@ The application will be compiled and copied onto your device
 
 - Custom wallet security
   - User specified password
-- USB/Bluetooth wallet functionality
+- USB/Bluetooth wallet functionality