Update Rust toolchain to 1.50.0

Bug: 180268112
Test: mm crosvm
Change-Id: Ib36f252a99e06059b413326b8f9d1733534facbc
diff --git a/rust/config/global.go b/rust/config/global.go
index 182dc6a..12f4972 100644
--- a/rust/config/global.go
+++ b/rust/config/global.go
@@ -24,7 +24,7 @@
 var pctx = android.NewPackageContext("android/soong/rust/config")
 
 var (
-	RustDefaultVersion = "1.49.0"
+	RustDefaultVersion = "1.50.0"
 	RustDefaultBase    = "prebuilts/rust/"
 	DefaultEdition     = "2018"
 	Stdlibs            = []string{