Bump shipkit-changelog from 1.1.13 to 1.1.15

Bumps shipkit-changelog from 1.1.13 to 1.1.15.

Signed-off-by: dependabot[bot] <support@github.com>

build.gradle

@@ -11,7 +11,7 @@ buildscript {
 
         //Using buildscript.classpath so that we can resolve plugins from maven local, during local testing
         classpath "org.shipkit:shipkit-auto-version:1.1.8"
-        classpath "org.shipkit:shipkit-changelog:1.1.13"
+        classpath "org.shipkit:shipkit-changelog:1.1.15"
         classpath "com.jfrog.bintray.gradle:gradle-bintray-plugin:1.+"
 
         classpath 'com.google.googlejavaformat:google-java-format:1.10.0'