Build on Github Actions JVM failing

[smyrick]

Library Version
1.2.2

Describe the bug
Our Github actions pr check is failing to run unit tests. All of them are failing with the following error java.lang.NoClassDefFoundError

However on Travis CI all our builds are passing

Here is a full error

[ERROR] Input property can have a description  Time elapsed: 0.147 s  <<< ERROR!
java.lang.NoClassDefFoundError: com/expediagroup/graphql/generator/types/InputPropertyBuilderTest$Input property can have a description$result$1
	at com.expediagroup.graphql.generator.types.InputPropertyBuilderTest.Input property can have a description(InputPropertyBuilderTest.kt:49)
Caused by: java.lang.ClassNotFoundException: com.expediagroup.graphql.generator.types.InputPropertyBuilderTest$Input property can have a description$result$1
	at com.expediagroup.graphql.generator.types.InputPropertyBuilderTest.Input property can have a description(InputPropertyBuilderTest.kt:49)

The JDK used on GH Actions is Java/11.0.5/x64
On travis the JDK used is

• openjdk version "1.8.0_141"
• openjdk version "11.0.2" 2019-01-15

To Reproduce
See this PR: #451

[smyrick]

Resolved with #451