Remove guava for Kotlin builtin decapitalize (#460)

Fixes #459

Remove the guava library since all we are using it for is the case format changes

Author: smyrick

examples/spring/src/main/kotlin/com/expediagroup/graphql/examples/directives/CustomDirectiveWiringFactory.kt

@@ -19,7 +19,6 @@ package com.expediagroup.graphql.examples.directives
 import com.expediagroup.graphql.directives.KotlinDirectiveWiringFactory
 import com.expediagroup.graphql.directives.KotlinSchemaDirectiveEnvironment
 import com.expediagroup.graphql.directives.KotlinSchemaDirectiveWiring
-import com.google.common.base.CaseFormat
 import graphql.schema.GraphQLDirectiveContainer
 import kotlin.reflect.KClass
 
@@ -35,5 +34,4 @@ class CustomDirectiveWiringFactory : KotlinDirectiveWiringFactory(manualWiring =
     }
 }
 
-internal fun getDirectiveName(kClass: KClass<out Annotation>): String =
-    CaseFormat.UPPER_CAMEL.to(CaseFormat.LOWER_CAMEL, kClass.simpleName!!)
+internal fun getDirectiveName(kClass: KClass<out Annotation>): String = kClass.simpleName!!.decapitalize()

graphql-kotlin-schema-generator/pom.xml

@@ -16,7 +16,6 @@
     <properties>
         <project.root>${project.basedir}/..</project.root>
         <rxjava2.version>2.2.12</rxjava2.version>
-        <guava.version>28.0-jre</guava.version>
     </properties>
 
     <dependencies>
@@ -36,11 +35,6 @@
             <groupId>io.github.classgraph</groupId>
             <artifactId>classgraph</artifactId>
         </dependency>
-        <dependency>
-            <groupId>com.google.guava</groupId>
-            <artifactId>guava</artifactId>
-            <version>${guava.version}</version>
-        </dependency>
         <dependency>
             <groupId>com.fasterxml.jackson.module</groupId>
             <artifactId>jackson-module-kotlin</artifactId>

graphql-kotlin-schema-generator/src/main/kotlin/com/expediagroup/graphql/generator/types/DirectiveBuilder.kt

@@ -22,7 +22,6 @@ import com.expediagroup.graphql.generator.extensions.getPropertyAnnotations
 import com.expediagroup.graphql.generator.extensions.getSimpleName
 import com.expediagroup.graphql.generator.extensions.getValidProperties
 import com.expediagroup.graphql.generator.extensions.safeCast
-import com.google.common.base.CaseFormat
 import graphql.schema.GraphQLArgument
 import graphql.schema.GraphQLDirective
 import java.lang.reflect.Field
@@ -95,7 +94,7 @@ internal class DirectiveBuilder(generator: SchemaGenerator) : TypeBuilder(genera
     }
 }
 
-private fun String.normalizeDirectiveName() = CaseFormat.UPPER_CAMEL.to(CaseFormat.LOWER_CAMEL, this)
+private fun String.normalizeDirectiveName() = this.decapitalize()
 
 private fun Annotation.getDirectiveInfo(): DirectiveInfo? = this.annotationClass.annotations
     .filterIsInstance(GraphQLDirectiveAnnotation::class.java)