Scala 2.13.4 support

Author: andreaTP

.travis.yml

@@ -66,6 +66,10 @@ env:
     TRAVIS_JDK=adopt@~1.8.0-0
   - SCALA_VERSION=2.13.3
     TRAVIS_JDK=adopt@~1.11.0-0
+  - SCALA_VERSION=2.13.4
+    TRAVIS_JDK=adopt@~1.8.0-0
+  - SCALA_VERSION=2.13.4
+    TRAVIS_JDK=adopt@~1.11.0-0
 
 before_install: curl -Ls https://git.io/jabba | bash && . ~/.jabba/jabba.sh
 install: jabba install "$TRAVIS_JDK" && jabba use "$_" && java -Xmx32m -version

build.sbt

@@ -49,7 +49,7 @@ lazy val defaults = Seq(
     val earliest211 = 6
     val latest211 = 12
     val latest212 = 12
-    val latest213 = 3
+    val latest213 = 4
     val skipVersions = Set("2.11.9", "2.11.10")
     val scala211Versions =
       (earliest211 to latest211)