Add updated usage to the README

README.md

@@ -21,7 +21,8 @@ $ cargo install blocktop
 ## Usage ##
 
 ```
-$ blocktop -h
+A minimalist TUI block explorer for Ethereum blockchains
+
 Usage: blocktop [OPTIONS]
 
 Options:
@@ -30,6 +31,7 @@ Options:
       --headless           
       --list-block-hashes  
   -h, --help               Print help
+  -V, --version            Print version
 ```
 
 At the moment, `blocktop` only supports Websockets or Unix domain sockets as transports for RPC communication. `blocktop` makes use of the [free Ethereum RPC service provided by Merkle](https://merkle.io/free-eth-rpc) by default.