Update README.md

Author: aminya

README.md

@@ -68,10 +68,11 @@ publicly hosted version thereof. In particular:
 
 It is possible to run FemtoCleaner locally (to fix, for example, deprecations in a private repository).
 
-Install `FemtoCleaner` (currently working on Julia v0.6.x only) using
+Install `FemtoCleaner` (currently working on Julia v0.6.x only https://julialang.org/downloads/oldreleases.html ) using
 
 ```jl
 Pkg.clone("https://github.com/Keno/AbstractTrees.jl")
+Pkg.checkout("AbstractTrees.jl","kf/for06")
 Pkg.clone("https://github.com/JuliaComputing/Deprecations.jl")
 Pkg.clone("https://github.com/JuliaComputing/FemtoCleaner.jl")
 ```