docs(readme): remove old migration guide (#236)

README.md

@@ -6,80 +6,6 @@ This library provides convenient access to the Anthropic REST API from server-si
 
 For the AWS Bedrock API, see [`@anthropic-ai/bedrock-sdk`](https://github.com/anthropics/anthropic-bedrock-typescript).
 
-## Migration from v0.4.x and below
-
-In `v0.5.0`, we introduced a fully rewritten SDK. The new version offers better error handling, a more robust and intuitive streaming implementation, and more.
-
-Key interface changes:
-
-1. `new Client(apiKey)` → `new Anthropic({ apiKey })`
-2. `client.complete()` → `client.completions.create()`
-3. `client.completeStream()` → `client.completions.create({ stream: true })`
-   1. `onUpdate` callback → `for await (const x of stream)`
-   2. full message in stream → delta of message in stream
-
-<details>
-<summary>Example diff</summary>
-
-```diff ts
-  // Import "Anthropic" instead of "Client":
-- import { Client, HUMAN_PROMPT, AI_PROMPT } from '@anthropic-ai/sdk';
-+ import Anthropic, { HUMAN_PROMPT, AI_PROMPT } from '@anthropic-ai/sdk';
-
-  // Instantiate with "apiKey" as an object property:
-- const client = new Client(apiKey);
-+ const client = new Anthropic({ apiKey });
-  // or, simply provide an ANTHROPIC_API_KEY environment variable:
-+ const client = new Anthropic();
-
-  async function main() {
-    // Request & response types are the same as before, but better-typed.
-    const params = {
-      prompt: `${HUMAN_PROMPT} How many toes do dogs have?${AI_PROMPT}`,
-      max_tokens_to_sample: 200,
-      model: "claude-1",
-    };
-
-    // Instead of "client.complete()", you now call "client.completions.create()":
--   await client.complete(params);
-+   await client.completions.create(params);
-
-    // Streaming requests now use async iterators instead of callbacks:
--   client.completeStream(params, {
--     onUpdate: (completion) => {
--       console.log(completion.completion); // full text
--     },
--   });
-+   const stream = await client.completions.create({ ...params, stream: true });
-+   for await (const completion of stream) {
-+     process.stdout.write(completion.completion); // incremental text
-+   }
-
-    // And, since this library uses `Anthropic-Version: 2023-06-01`,
-    // completion streams are now incremental diffs of text
-    // rather than sending the whole message every time:
-    let text = '';
--   await client.completeStream(params, {
--     onUpdate: (completion) => {
--       const diff = completion.completion.replace(text, "");
--       text = completion.completion;
--       process.stdout.write(diff);
--     },
--   });
-+   const stream = await client.completions.create({ ...params, stream: true });
-+   for await (const completion of stream) {
-+     const diff = completion.completion;
-+     text += diff;
-+     process.stdout.write(diff);
-+   }
-    console.log('Done; final text is:')
-    console.log(text)
-  }
-  main();
-```
-
-</details>
-
 The API documentation can be found [here](https://docs.anthropic.com/claude/reference/).
 
 ## Installation