Update the installation instructions

README.md

@@ -19,18 +19,15 @@ CFML consists of two parts:
 Installation
 ============
 
-The current version of CFML requires Coq 8.6 (*not* 8.6.1).
+The current version of CFML requires Coq 8.6 or newer.
 
 The simplest way of installing the *latest released version* of CFML is via `opam`.
 
-It is recommended to create a new switch, whose name you can choose;
-in the following, we use `cfml86`.
-
 ```sh
-opam switch cfml86 -A 4.05.0
-eval `opam config env`
-opam install -j4 coq.8.6
-opam install -j4 coq-cfml
+# This only needs to be done once, to add the opam repository with coq packages
+opam repo add coq-released https://coq.inria.fr/opam/released
+
+opam install coq-cfml
 ```
 
 If instead you wish to use *the development version* of CFML,