Update test-release and readme versions (#343)

Author: ckipp01

README.md

@@ -3,9 +3,9 @@
 ![build](https://github.com/scoverage/scalac-scoverage-plugin/workflows/build/badge.svg)
 [![Gitter](https://img.shields.io/gitter/room/scoverage/scoverage.svg)](https://gitter.im/scoverage/scoverage)
 [![Maven Central](https://img.shields.io/maven-central/v/org.scoverage/scalac-scoverage-plugin_2.10.svg?label=latest%20release%20for%202.10)](http://search.maven.org/#search|ga|1|g%3A%22org.scoverage%22%20AND%20a%3A%22scalac-scoverage-plugin_2.10%22)
-[![Maven Central](https://img.shields.io/maven-central/v/org.scoverage/scalac-scoverage-plugin_2.11.svg?label=latest%20release%20for%202.11)](http://search.maven.org/#search|ga|1|g%3A%22org.scoverage%22%20AND%20a%3A%22scalac-scoverage-plugin_2.11%22)
+[![Maven Central](https://img.shields.io/maven-central/v/org.scoverage/scalac-scoverage-plugin_2.11.12.svg?label=latest%202.11%20Scala%20support%20[2.11.12]%20and%20latest%20version)](http://search.maven.org/#search|ga|1|g%3A%22org.scoverage%22%20AND%20a%3A%22scalac-scoverage-plugin_2.11.12%22)
 [![Maven Central](https://img.shields.io/maven-central/v/org.scoverage/scalac-scoverage-plugin_2.12.13.svg?label=latest%202.12%20Scala%20support%20[2.12.13]%20and%20latest%20version)](http://search.maven.org/#search|ga|1|g%3A%22org.scoverage%22%20AND%20a%3A%22scalac-scoverage-plugin_2.12.13%22)
-[![Maven Central](https://img.shields.io/maven-central/v/org.scoverage/scalac-scoverage-plugin_2.13.5.svg?label=latest%202.13%20Scala%20support%20[2.13.5]%20and%20version)](http://search.maven.org/#search|ga|1|g%3A%22org.scoverage%22%20AND%20a%3A%22scalac-scoverage-plugin_2.13.5%22)
+[![Maven Central](https://img.shields.io/maven-central/v/org.scoverage/scalac-scoverage-plugin_2.13.6.svg?label=latest%202.13%20Scala%20support%20[2.13.6]%20and%20version)](http://search.maven.org/#search|ga|1|g%3A%22org.scoverage%22%20AND%20a%3A%22scalac-scoverage-plugin_2.13.6%22)
 [![License](http://img.shields.io/:license-Apache%202-red.svg)](http://www.apache.org/licenses/LICENSE-2.0.txt)
 
 scoverage is a free Apache licensed code coverage tool for Scala that offers

bin/test-release.sh

@@ -4,6 +4,7 @@ set -eux
 version=$1
 
 coursier fetch \
+  org.scoverage:scalac-scoverage-plugin_2.11.12:$version \
   org.scoverage:scalac-scoverage-plugin_2.12.8:$version \
   org.scoverage:scalac-scoverage-plugin_2.12.9:$version \
   org.scoverage:scalac-scoverage-plugin_2.12.10:$version \
@@ -16,7 +17,10 @@ coursier fetch \
   org.scoverage:scalac-scoverage-plugin_2.13.4:$version \
   org.scoverage:scalac-scoverage-plugin_2.13.5:$version \
   org.scoverage:scalac-scoverage-plugin_2.13.5:$version \
+  org.scoverage:scalac-scoverage-plugin_2.13.6:$version \
+  org.scoverage:scalac-scoverage-runtime_2.11:$version \
   org.scoverage:scalac-scoverage-runtime_2.12:$version \
   org.scoverage:scalac-scoverage-runtime_2.13:$version \
+  org.scoverage:scalac-scoverage-runtime_sjs1_2.11:$version \
   org.scoverage:scalac-scoverage-runtime_sjs1_2.12:$version \
   org.scoverage:scalac-scoverage-runtime_sjs1_2.13:$version \