Update kotlin monorepo (#1614)

* Update kotlin monorepo

* Update ksp to v1.8.0-1.0.9

* Lower metadata to 0.5.0

* Update KCT

* Update to compilerOptions

* Suppress deprecation

* Add missing java target too

* Raise it again because it's broken on all

* Kotlin 1.8.20 + updated kotlinpoet

* Update kotlinpoet

* Update kotlin

* Fix KSP equality check for KotlinPoet 1.13.x

---------

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>
Co-authored-by: Jake Wharton <github@jakewharton.com>
Co-authored-by: Zac Sweers <pandanomic@gmail.com>

moshi-kotlin-tests/codegen-only/build.gradle.kts

@@ -35,14 +35,10 @@ tasks.withType<Test>().configureEach {
   jvmArgs("--add-opens=java.base/java.io=ALL-UNNAMED")
 }
 
-val useWError = findProperty("kotlinLanguageVersion")?.toString()
-  ?.startsWith("1.5")
-  ?: false
 tasks.withType<KotlinCompile>().configureEach {
-  kotlinOptions {
-    allWarningsAsErrors = useWError
-    @Suppress("SuspiciousCollectionReassignment")
-    freeCompilerArgs += listOf(
+  compilerOptions {
+    allWarningsAsErrors.set(true)
+    freeCompilerArgs.add(
       "-opt-in=kotlin.ExperimentalStdlibApi",
     )
   }