chore(docs): add example project (#367)

Author: stainless-app[bot]

finch-java-example/build.gradle.kts

@@ -1,12 +1,18 @@
 plugins {
-    id("application")
-    id("finch.java")
+    id("finch.kotlin")
+    id("java")
+    application
 }
 
 dependencies {
     implementation(project(":finch-java"))
 }
 
+tasks.withType<JavaCompile>().configureEach {
+    // Allow using more modern APIs, like `List.of` and `Map.of`, in examples.
+    options.release.set(9)
+}
+
 application {
-    mainClass.set("com.tryfinch.api.example.Main")
+    mainClass = "com.tryfinch.api.example.Main"
 }