Update AGP, SDK, and BillingClient

This commit updates:
- Android Gradle Plugin to 8.11.0
- Compile/Target SDK to 36
- Google Play Billing Library to 8.0.0

The `BillingClient` is updated to use the new `PendingPurchasesParams` and `QueryPurchasesParams` APIs.

buildSrc/build.gradle.kts

@@ -8,7 +8,7 @@ repositories {
     mavenCentral()
 }
 dependencies {
-    implementation("com.android.tools.build:gradle:8.10.1")
+    implementation("com.android.tools.build:gradle:8.11.0")
     implementation("org.jetbrains.kotlin:kotlin-gradle-plugin:2.1.21")
     implementation("com.squareup:javapoet:1.13.0")
 }

buildSrc/src/main/java/ProjectConfig.kt

@@ -11,8 +11,8 @@ object ProjectConfig {
     const val packageName = "eu.darken.capod"
 
     const val minSdk = 26
-    const val compileSdk = 34
-    const val targetSdk = 34
+    const val compileSdk = 36
+    const val targetSdk = 36
 
     object Version {
         val versionProperties = Properties().apply {