docs: note JDK 17 requirement for Gradle builds

Clarifies Android Studio Gradle JDK setting to avoid Java 11
resolution failures with baseline profile plugin dependencies.

Fixes #1137

README.md

@@ -30,7 +30,12 @@ in, and be notified when new content is published which matches interests they a
 
 # Development Environment
 
-**Now in Android** uses the Gradle build system and can be imported directly into Android Studio (make sure you are using the latest stable version available [here](https://developer.android.com/studio)). 
+**Now in Android** uses the Gradle build system and can be imported directly into Android Studio (make sure you are using the latest stable version available [here](https://developer.android.com/studio)).
+
+> **Note:** This project requires **JDK 17** for Gradle. In Android Studio, set
+> **Settings → Build, Execution, Deployment → Build Tools → Gradle → Gradle JDK** to **17**
+> (or **Embedded JDK** on recent Studio versions). Using JDK 11 will fail when resolving
+> the baseline profile Gradle plugin and other dependencies that target Java 17.
 
 Change the run configuration to `app`.