Add usdc/usd price feed info (#46)

Author: ali-behjati

pyth-sdk-terra/README.md

@@ -67,6 +67,7 @@ List of available Price Feeds and their ids:
 | Crypto.LUNA/USD | `0x6de025a4cf28124f8ea6cb8085f860096dbc36d9c40002e221fc449337e065b2` |
 | Crypto.UST/USD  | `0x026d1f1cf9f1c0ee92eb55696d3bd2393075b611c4f468ae5b967175edc4c25c` |
 | Crypto.ALGO/USD | `0x08f781a893bc9340140c5f89c8a96f438bcfae4d1474cc0f688e3a52892c7318` |
+| Crypto.USDC/USD | `0x41f3625971ca2ed2263e78573fe5ce23e13d2558ed3f2e47ab0f84fb9e7ae722` |
 
 Testnet price feeds update once per minute.