[typeshare] Support external tags for enums

[naveenOnarayanan]

Description

• For complex enums the default serde serialization is externally tagged, to avoid having to re-write our rust logic to use internal tags via #[serde(tag = "type", content = "content")] we are going to add manual support for it in typescript
• Bumping version to 1.12.1
• Adding a --dry-run flag to allow building locally

Before

# Rust
enum MyEnum {
  blahblah {
    name: String
  }
  blahblah2 {
    age: u64
  }
}

# Typescript
export type MyEnum = 
  { "type": "blahblah", content: { "name": string }}
  | { "type": "blahblah2", content: { "age": number }}

After

export type MyEnum =
 { "blahblah": { "name": string }}
| { "blahblah2": { "age": number }}

Test Plan

• CI passes

Revert Plan

• Revert