Update evm.mdx (#595)

qdd bera to the index

Author: KemarTiti

pages/price-feeds/sponsored-feeds/evm.mdx

@@ -4,6 +4,7 @@ At the time of writing, the following EVM chains have sponsored price feeds:
 
 - [Ethereum Mainnet](#ethereum-mainnet)
 - [Base Mainnet](#base-mainnet)
+- [Berachain Mainnet](#berachain-mainnet)
 - [Kraken Mainnet](#kraken-mainnet)
 - [Mode Mainnet](#mode-mainnet)
 - [Sonic Mainnet](#sonic-mainnet)