docs: mention its the default plugin

pvdlg · gr2m · commit ab91f82ebba1 · 2018-01-30T11:00:41.000-08:00
diff --git a/README.md b/README.md
@@ -165,3 +165,7 @@ The following example uses [Angular convention](https://github.com/conventional-
   }
 }
 ```
+
+## Usage
+
+The plugin is used by default by [semantic-release](https://github.com/semantic-release/semantic-release) so installing it is not necessary and all configuration are optionals.

Original file line number	Diff line number	Diff line change
`@@ -165,3 +165,7 @@ The following example uses [Angular convention](https://github.com/conventional-`
`165`	`165`	`}`
`166`	`166`	`}`
`167`	`167`	```
	`168`	`+`
	`169`	`+## Usage`
	`170`	`+`
	`171`	`+The plugin is used by default by [semantic-release](https://github.com/semantic-release/semantic-release) so installing it is not necessary and all configuration are optionals.`