Update gradle command

Ashish Bhatia · mkalinin · commit 1935318e4011 · 2018-10-12T16:08:23.000+06:00
Replace compile with implementation as recommended here: https://docs.gradle.org/current/userguide/java_library_plugin.html#sec:java_library_separation
diff --git a/README.md b/README.md
@@ -30,7 +30,7 @@ We keep EthereumJ as thin as possible. For [JSON-RPC](https://github.com/ethereu
        jcenter()
        maven { url "https://dl.bintray.com/ethereum/maven/" }
    }
-   compile "org.ethereum:ethereumj-core:1.8.+"
+   implementation "org.ethereum:ethereumj-core:1.8.+"
 ```
 
 As a starting point for your own project take a look at https://github.com/ether-camp/ethereumj.starter

Original file line number	Diff line number	Diff line change
`@@ -30,7 +30,7 @@ We keep EthereumJ as thin as possible. For [JSON-RPC](https://github.com/ethereu`
`30`	`30`	`jcenter()`
`31`	`31`	`maven { url "https://dl.bintray.com/ethereum/maven/" }`
`32`	`32`	`}`
`33`		`- compile "org.ethereum:ethereumj-core:1.8.+"`
	`33`	`+ implementation "org.ethereum:ethereumj-core:1.8.+"`
`34`	`34`	```
`35`	`35`
`36`	`36`	`As a starting point for your own project take a look at https://github.com/ether-camp/ethereumj.starter`