misc: add a section about GraalVM target (#1345)

Author: lauzadis

README.md

@@ -153,4 +153,5 @@ Please refer to our [security policy](https://github.com/awslabs/aws-sdk-kotlin/
 The SDK supports the following targets:
 
 * [JVM](docs/targets.md#jvm)
-* [Android](docs/targets.md#android) 
+* [Android](docs/targets.md#android)
+* [GraalVM](docs/targets.md#graalvm)

docs/targets.md

@@ -41,3 +41,12 @@ dependencies {
     coreLibraryDesugaring("com.android.tools:desugar_jdk_libs:1.1.5")
 }
 ```
+
+## GraalVM
+
+The AWS SDK for Kotlin supports [native image compilation using GraalVM](https://www.graalvm.org/latest/reference-manual/native-image/).
+
+Compiling native images is easily accomplished by applying [the GraalVM build plugin](https://github.com/graalvm/native-build-tools) to your application and running `./gradlew nativeCompile`.
+View [their getting started guide](https://graalvm.github.io/native-build-tools/latest/gradle-plugin-quickstart.html) for further details.
+
+NOTE: [log4j2 does not currently support](https://github.com/apache/logging-log4j2/issues/1539) GraalVM native image compilation, so we recommend selecting a different logger implementation such as Logback.