document roadmap to v1.0.0

Author: rursprung

README.md

@@ -29,6 +29,10 @@ A simple example for the STM32F4 microcontrollers is [available](examples/stm32f
 ## Changelog
 For the changelog please see the dedicated [CHANGELOG.md](CHANGELOG.md).
 
+## Roadmap to v1.0.0
+This crate is already stable, however it's based on a 0.x version of [`embedded-hal`](https://github.com/rust-embedded/embedded-hal/), making the API unstable (the change from 0.x to 1.x of e-h will be breaking).
+See [the tracking issue](https://github.com/rursprung/tb6612fng-rs/issues/4) for the roadmap to v1.0.0.
+
 ## Minimum Supported Rust Version (MSRV)
 This crate is guaranteed to compile on stable Rust 1.60 and up. It *might*
 compile with older versions but that may change in any new patch release.