prepare release 2.0.0

Author: renanbr

README.md

@@ -38,7 +38,7 @@ You are browsing the documentation of **BibTeX Parser 2.x**, the latest version.
 ## Installing
 
 ```bash
-composer require renanbr/bibtex-parser ^2@dev
+composer require renanbr/bibtex-parser ^2
 ```
 
 ## Usage