docs: typo in README (#87)

Author: gtchance

README.md

@@ -32,7 +32,7 @@ claims.issuer = "fuller.li"
 claims.issuedAt = Date()
 claims["custom"] = "Hi"
 
-JWT.encode(claims: claims, algorithm, algorithm: .hs256("secret".data(using: .utf8)))
+JWT.encode(claims: claims, algorithm: .hs256("secret".data(using: .utf8)))
 ```
 
 #### Building a JWT with the builder pattern