Support Scala 2.12.10 (#194)

Author: wangyum

Diff for: .travis.yml

@@ -16,6 +16,7 @@ env:
   - SCALA_VERSION=2.12.7
   - SCALA_VERSION=2.12.8
   - SCALA_VERSION=2.12.9
+  - SCALA_VERSION=2.12.10
   - SCALA_VERSION=2.13.0
 
 # 2.11.12 was the first Scala 2.11.x version to work on jdk11

Diff for: RELEASING.md

@@ -15,6 +15,6 @@ 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.
 2. 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.
-3. Change the Scala version to the release you want to perform, this is done by `++2.12.9` in the sbt command line.
+3. Change the Scala version to the release you want to perform, this is done by `++2.12.10` in the sbt command line.
 4. Publish the release by running `sbt publishSigned`. You will need Sonatype OSS repository rights to publish under `com.typesafe` organisation.
 5. Login to [Sonatype](https://oss.sonatype.org/) to close and release the repository.

Diff for: build.sbt

@@ -55,7 +55,7 @@ lazy val defaults = Seq(
   crossScalaVersions := {
     val earliest211 = 6
     val latest211 = 12
-    val latest212 = 9
+    val latest212 = 10
     val latest213 = 0
     val skipVersions = Set("2.11.9", "2.11.10")
     val scala211Versions =