chore: update codegen test utils dependency (#794)

Author: ianbotsf

codegen/smithy-aws-kotlin-codegen/build.gradle.kts

@@ -35,6 +35,7 @@ dependencies {
     testImplementation("org.junit.jupiter:junit-jupiter-params:$junitVersion")
     testImplementation("io.kotest:kotest-assertions-core-jvm:$kotestVersion")
     testImplementation("org.jetbrains.kotlin:kotlin-test-junit5:$kotlinVersion")
+    testImplementation("software.amazon.smithy.kotlin:smithy-kotlin-codegen-testutils:$smithyKotlinVersion")
 
     testImplementation("org.slf4j:slf4j-api:$slf4jVersion")
     testImplementation("org.slf4j:slf4j-simple:$slf4jVersion")