Version 2.0.0

- Use `once_cell` instead of `lazy_static` for test
- Comply with Clippy rules
- More small fixes

The following changes has been included since 2.0.0-beta.1.

- Use phf (perfect hash map) instead of ahash (#7, #9) by @mkroening
  Actual type of OEMCPHashMap will be changed.

Author: tats-u

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "oem_cp"
-version = "2.0.0-beta.1"
+version = "2.0.0"
 authors = ["Tatsunori Uchino <[email protected]>"]
 edition = "2021"
 categories = ["encoding"]