codegen: Upgrade to Smithy IDL 2.0 (#1806)

- Upgrade `smithyVersion` to 1.23.1
- Extract Smithy Gradle Plugin to `smithyGradleVersion` to 0.6.0
- Add support for `jsonName` serialization/deserialization for union shapes

codegen/gradle.properties

@@ -1 +1,2 @@
-smithyVersion=1.21.0
+smithyVersion=1.23.1
+smithyGradleVersion=0.6.0

codegen/protocol-test-codegen/build.gradle.kts

@@ -28,7 +28,8 @@ buildscript {
 }
 
 plugins {
-    id("software.amazon.smithy") version "0.5.3"
+    val smithyGradleVersion: String by project
+    id("software.amazon.smithy") version smithyGradleVersion
 }
 
 dependencies {

codegen/sdk-codegen/build.gradle.kts

@@ -33,7 +33,8 @@ buildscript {
 }
 
 plugins {
-    id("software.amazon.smithy") version "0.5.3"
+    val smithyGradleVersion: String by project
+    id("software.amazon.smithy") version smithyGradleVersion
 }
 
 dependencies {

codegen/smithy-aws-go-codegen/src/main/java/software/amazon/smithy/aws/go/codegen/JsonShapeDeserVisitor.java

@@ -231,8 +231,9 @@ protected void deserializeUnion(GenerationContext context, UnionShape shape) {
                             symbolProvider.toMemberName(member),
                             symbol.getNamespace()
                     ).build();
+                    String serializedMemberName = getSerializedMemberName(member);
 
-                    writer.openBlock("case $S:", "", member.getMemberName(), () -> {
+                    writer.openBlock("case $S:", "", serializedMemberName, () -> {
                         writer.write("var mv $P", targetSymbol);
                         target.accept(getMemberDeserVisitor(member, "mv"));
 

codegen/smithy-aws-go-codegen/src/main/java/software/amazon/smithy/aws/go/codegen/JsonShapeSerVisitor.java

@@ -235,9 +235,10 @@ protected void serializeUnion(GenerationContext context, UnionShape shape) {
                         symbolProvider.toMemberName(member),
                         symbol.getNamespace()
                 ).build();
+                String serializedMemberName = getSerializedMemberName(member);
 
                 writer.openBlock("case *$T:", "", memberSymbol, () -> {
-                    writer.write("av := object.Key($S)", member.getMemberName());
+                    writer.write("av := object.Key($S)", serializedMemberName);
                     target.accept(getMemberSerVisitor(member, "uv.Value", "av"));
                 });
             }