chore(docs): update README stable to 0.2.1

Author: mookums

README.md

@@ -20,9 +20,9 @@ tardy is a thread-local, I/O driven runtime for Zig, providing the core implemen
 ## Installing
 Latest Zig Stable: `0.13.0`
 
-Latest tardy Release: `0.2.0`
+Latest tardy Release: `0.2.1`
 ```
-zig fetch --save git+https://github.com/tardy-org/tardy#v0.2.0
+zig fetch --save git+https://github.com/tardy-org/tardy#v0.2.1
 ```
 
 You can then add the dependency in your `build.zig` file: