docs(readme): remove beta status + document versioning policy (#54)

Author: stainless-bot

README.md

@@ -268,10 +268,15 @@ See the httpx documentation for information about the [`proxies`](https://www.py
 
 By default we will close the underlying HTTP connections whenever the client is [garbage collected](https://docs.python.org/3/reference/datamodel.html#object.__del__) is called but you can also manually close the client using the `.close()` method if desired, or with a context manager that closes when exiting.
 
-## Status
+## Versioning
 
-This package is in beta. Its internals and interfaces are not stable and subject to change without a major semver bump;
-please reach out if you rely on any undocumented behavior.
+This package generally attempts to follow [SemVer](https://semver.org/spec/v2.0.0.html) conventions, though certain backwards-incompatible changes may be released as minor versions:
+
+1. Changes that only affect static types, without breaking runtime behavior.
+2. Changes to library internals which are technically public but not intended or documented for external use. _(Please open a GitHub issue to let us know if you are relying on such internals)_.
+3. Changes that we do not expect to impact the vast majority of users in practice.
+
+We take backwards-compatibility seriously and work hard to ensure you can rely on a smooth upgrade experience.
 
 We are keen for your feedback; please open an [issue](https://www.github.com/Finch-API/finch-api-python/issues) with questions, bugs, or suggestions.