Release 0.0.12

Remove reference to JDK 7 in example configuration, now that
support for it has been removed.

README.md

@@ -25,6 +25,7 @@ It also depends on Javac internal APIs, directly exposed by error-prone.
  0.0.9                             | 2.6 - 3.4                 | 1.+¹, 2.+                     | 7, 8
  0.0.10                            | 2.6 - 4.2                 | 1.+¹, 2.+                     | 7, 8
  0.0.11                            | 2.6 - 4.2                 | 1.+¹, 2.+                     | 7, 8
+ 0.0.12                            | 2.6 - 4.2                 | 2.+                           | 8
  _master_                          | 2.6 - 4.2                 | 2.+                           | 8
 
 ¹: error-prone 1.x is only supported with JDK 7
@@ -68,8 +69,7 @@ You can override it to use a specific version with:
 
 ```groovy
 dependencies {
-  // 2.0.5 is the last version compatible with JDK 7
-  errorprone 'com.google.errorprone:error_prone_core:2.0.5'
+  errorprone 'com.google.errorprone:error_prone_core:2.0.21'
 }
 ```