Use modern syntax for dependency

Xaseron · web-flow · commit 6ae9af72d44f · 2020-12-27T19:05:32.000+01:00
This syntax is compatible with Kotlin and Groovy. 
Therefore it is easier for new users to just copy and paste the dependency.
diff --git a/README.md b/README.md
@@ -39,7 +39,7 @@ repositories {
     jcenter()
 }
 
-compile group: 'com.adamratzman', name: 'spotify-api-kotlin-core', version: '3.2.15'
+implementation("com.adamratzman:spotify-api-kotlin-core:3.2.15")
 ```
 
 Note that images and profiles are not supported on the Kotlin/JS target.

Original file line number	Diff line number	Diff line change
`@@ -39,7 +39,7 @@ repositories {`
`39`	`39`	`jcenter()`
`40`	`40`	`}`
`41`	`41`
`42`		`-compile group: 'com.adamratzman', name: 'spotify-api-kotlin-core', version: '3.2.15'`
	`42`	`+implementation("com.adamratzman:spotify-api-kotlin-core:3.2.15")`
`43`	`43`	```
`44`	`44`
`45`	`45`	`Note that images and profiles are not supported on the Kotlin/JS target.`