Version bumped to v2.0.0

Author: tailhook

Cargo.toml

@@ -4,7 +4,7 @@ description = """
     A macro which makes error types pleasant to write.
 """
 license = "MIT/Apache-2.0"
-version = "1.2.3"
+version = "2.0.0"
 edition = "2018"
 keywords = ["macro", "error", "type", "enum"]
 authors = ["Paul Colomiets <paul@colomiets.name>", "Colin Kiegel <kiegel@gmx.de>"]