Add support for Scala 2.12.13

Author: marcospereira

.travis.yml

@@ -50,6 +50,10 @@ env:
     TRAVIS_JDK=adopt@~1.8.0-0
   - SCALA_VERSION=2.12.12
     TRAVIS_JDK=adopt@~1.11.0-0
+  - SCALA_VERSION=2.12.13
+    TRAVIS_JDK=adopt@~1.8.0-0
+  - SCALA_VERSION=2.12.13
+    TRAVIS_JDK=adopt@~1.11.0-0
   - SCALA_VERSION=2.13.0
     TRAVIS_JDK=adopt@~1.8.0-0
   - SCALA_VERSION=2.13.0

RELEASING.md

@@ -15,4 +15,4 @@ It is often the case when this compiler plugin needs to be released for a newly
   * master, if no features or bug fixes were merged to master since the latest release
   * tag, if the master has unreleased features or bug fixes. In this case you will need to cherry pick the commit that adds support for the new Scala version.
 1. Create a file `version.sbt` containing `version in ThisBuild := "0.11"` which sets the version to be back-released. This will override the automatic version derivation from the git history. Alternatively you can `set version in ThisBuild := ...` in the command line.
-1. Publish the release by running `SONATYPE_USERNAME=xxx SONATYPE_PASSWORD=xxx sbt ++2.12.12 publishSigned sonatypeBundleRelease` (with the appropriate credentials and scala version). You will need Sonatype OSS repository rights to publish under `com.typesafe` organisation.
+1. Publish the release by running `SONATYPE_USERNAME=xxx SONATYPE_PASSWORD=xxx sbt ++2.12.13 publishSigned sonatypeBundleRelease` (with the appropriate credentials and scala version). You will need Sonatype OSS repository rights to publish under `com.typesafe` organisation.

build.sbt

@@ -48,7 +48,7 @@ lazy val defaults = Seq(
   crossScalaVersions := {
     val earliest211 = 6
     val latest211 = 12
-    val latest212 = 12
+    val latest212 = 13
     val latest213 = 4
     val skipVersions = Set("2.11.9", "2.11.10")
     val scala211Versions =