Updated URL of the JavaScript reference implementation

Old repo is archived and links to the new repo are found in the old one's README file. This change updates the old repo's link to the new one.

Author: chirag64

bip-0039.mediawiki

@@ -163,7 +163,7 @@ Haskell:
 * https://github.com/NicolasDorier/NBitcoin
 
 JavaScript:
-* https://github.com/bitpay/bitcore-mnemonic
+* https://github.com/bitpay/bitcore/tree/master/packages/bitcore-mnemonic
 * https://github.com/bitcoinjs/bip39 (used by [[https://github.com/blockchain/My-Wallet-V3/blob/v3.8.0/src/hd-wallet.js#L121-L146|blockchain.info]])
 
 Java: