message: docs: remove hard coded version link from readme
  Motivation:
  When a user clicks they they may accidentally get an old version of the crate. Its also out of sync with the current main readme.
  Solution:
  removed the hard coded links
diff: @@ -16,9 +16,9 @@ Application-level tracing for Rust.
  [Documentation][docs-url] | [Chat][discord-url]
  [crates-badge]: https://img.shields.io/crates/v/tracing.svg
  -[crates-url]: https://crates.io/crates/tracing/0.1.21
  +[crates-url]: https://crates.io/crates/tracing
  [docs-badge]: https://docs.rs/tracing/badge.svg
  -[docs-url]: https://docs.rs/tracing/0.1.21
  +[docs-url]: https://docs.rs/tracing
  [docs-master-badge]: https://img.shields.io/badge/docs-master-blue
  [docs-master-url]: https://tracing-rs.netlify.com/tracing
  [mit-badge]: https://img.shields.io/badge/license-MIT-blue.svg
  