Change version to 1.45.0 in README (#1770)

Author: fanlong

README.md

@@ -8,7 +8,7 @@ and
 [run](https://developer.conflux-chain.org/docs/conflux-doc/docs/get_started)
 Conflux.
 
-This version depends on rustc 1.42.0.
+This version depends on rustc 1.45.0.
 
 ## Contribution