chore: fix README

Author: AlexChetverov

README.md

@@ -123,7 +123,7 @@ npx hardhat run scripts/callRawPrecompile.ts
 SHA256 result for 0x47617465776179 is: 0x41ed52921661c7f0d68d92511589cc9d7aaeab2b5db49fb27f0be336cbfdb7df
 ```
 
-We can check that "Gateway" is "0x41ed52921661c7f0d68d92511589cc9d7aaeab2b5db49fb27f0be336cbfdb7df" in SHA256 by using any SHA256 encrypter (e.g. https://10015.io/tools/sha256-encrypt-decrypt)
+We can check that "Gateway" is "0x41ed52921661c7f0d68d92511589cc9d7aaeab2b5db49fb27f0be336cbfdb7df" in SHA256 by using any SHA256 encrypter (e.g. https://md5calc.com/hash/sha256/Gateway)
 
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