codegen: Fix enum value generated name to not be lower cased

Fixes the generated enum value names to not be lower cased when
capitalized.

Related to aws/aws-sdk-go-v2#1013

codegen/smithy-go-codegen/src/main/java/software/amazon/smithy/go/codegen/EnumGenerator.java

@@ -16,7 +16,6 @@
 package software.amazon.smithy.go.codegen;
 
 import java.util.LinkedHashSet;
-import java.util.Locale;
 import java.util.Set;
 import java.util.logging.Logger;
 import software.amazon.smithy.codegen.core.Symbol;
@@ -60,7 +59,7 @@ public void run() {
                     StringBuilder labelBuilder = new StringBuilder(symbol.getName());
                     String name = definition.getName().get();
                     for (String part : name.split("(?U)[\\W_]")) {
-                        labelBuilder.append(StringUtils.capitalize(part.toLowerCase(Locale.US)));
+                        labelBuilder.append(StringUtils.capitalize(part));
                     }
                     String label = labelBuilder.toString();