Add version badge to README

Author: K-dizzled

README.md

@@ -1,5 +1,7 @@
 # CoqPilot
 
+![Version](https://img.shields.io/badge/version-v2.3.0-blue?style=flat-square)
+
 *Authors:* Andrei Kozyrev, Gleb Solovev, Nikita Khramov, and Anton Podkopaev, [Programming Languages and Tools Lab](https://lp.jetbrains.com/research/plt_lab/) at JetBrains Research.
 
 `CoqPilot` is a [Visual Studio Code](https://code.visualstudio.com/) extension that is designed to help automate writing of Coq proofs. It uses Large Language Models to generate multiple potential proofs and then uses [coq-lsp](https://github.com/ejgallego/coq-lsp) to typecheck them. It substitutes the proof in the editor only if a valid proof is found.