change network to bitvm signet (BitVM#228)

Author: wz14

bridge/src/client/esplora.rs

@@ -3,11 +3,12 @@ use bitcoin::Network;
 const REGTEST_ESPLORA_URL: &str = "http://localhost:8094/regtest/api/";
 // This endpoint accepts non-standard transactions.
 const ALPEN_SIGNET_ESPLORA_URL: &str = "https://esplora-large.devnet-annapurna.stratabtc.org";
+const BITVM_SIGNET_ESPLORA_URL: &str = "https://esplora.bitvmnet.org";
 
 // TODO: Needs to be updated for production environment.
 pub fn get_esplora_url(network: Network) -> &'static str {
     match network {
         Network::Regtest => REGTEST_ESPLORA_URL,
-        _ => ALPEN_SIGNET_ESPLORA_URL,
+        _ => BITVM_SIGNET_ESPLORA_URL,
     }
 }