Clarify which crate versions have which MSRVs (#79)

* Update README.md

* Update lib.rs

* Update README.md

Author: JSorngard

README.md

@@ -14,8 +14,8 @@ or check whether a number is prime in a const function.
 
 `no_std` compatible when the `serde` feature is disabled.
 
-This version supports Rust versions 1.81.0 and up, while previous versions
-support Rust versions 1.67.1 and up.
+This version of the crate supports Rust versions 1.81.0 and up, 
+while versions 0.8.7 and older support Rust versions 1.67.1 and up.
 
 ## Example: generate primes at compile time and use them for related computations
 

src/lib.rs

@@ -5,7 +5,7 @@
 //!
 //! `no_std` compatible when the `serde` feature is disabled.
 //!
-//! This version supports Rust versions 1.81.0 and up, while versions 0.8.7 and older support Rust versions 1.67.1 and up.
+//! This version of the crate supports Rust versions 1.81.0 and up, while versions 0.8.7 and older support Rust versions 1.67.1 and up.
 //!
 //! # Example: generate primes at compile time and reuse it for related computations
 //!