fix(doc) Update README

Signed-off-by: Jerome Simeon <[email protected]>

Author: jeromesimeon

README.md

@@ -3,26 +3,35 @@
 This is a minimal JavaScript syntax tree carved out of the
 [JsCert](https://github.com/jscert/jscert) project.
 
-## Prerequisites
+## Installation
+
+JsAst depends on:
+- Coq (version 8.11.2) or later
 
-You need the Flocq library for Coq:
+### From opam
 
 ```
 opam repo add coq-released https://coq.inria.fr/opam/released
-opam install coq-flocq
+opam install coq-jsast
 ```
 
-## Installation
+### Local with opam
 
-JsAst depends on:
-- Coq (version 8.7)
+In this directory:
+
+```
+opam install .
+```
+
+### From source
 
 To compile, do:
 ```
 make
 ```
 
-To install, do:
+To install as a Coq user contribution, do:
 ```
 make install
 ```
+