Add deprecation message (#58)

Author: DilumAluthge

README.md

@@ -1,27 +1,3 @@
-# GitCommand
+# GitCommand.jl: This package is deprecated.
 
-[![CI](https://github.com/JuliaVersionControl/GitCommand.jl/actions/workflows/ci.yml/badge.svg)](https://github.com/JuliaVersionControl/GitCommand.jl/actions/workflows/ci.yml)
-[![codecov](https://codecov.io/gh/JuliaVersionControl/GitCommand.jl/branch/master/graph/badge.svg?token=cdXpiH0OJ3)](https://codecov.io/gh/JuliaVersionControl/GitCommand.jl)
-
-GitCommand allows you to use command-line Git in your Julia packages. You do
-not need to have Git installed on your computer, and neither do the users of
-your packages!
-
-GitCommand provides a Git binary via
-[Git_jll](https://github.com/JuliaBinaryWrappers/Git_jll.jl).
-The latest version of GitCommand requires at least Julia 1.6.
-
-GitCommand is intended to work on any platform that supports Julia,
-including (but not limited to) Windows, macOS, Linux, and FreeBSD.
-
-## Examples
-
-```julia
-julia> using GitCommand
-
-julia> run(`$(git()) clone https://github.com/JuliaRegistries/General`)
-```
-
-## Acknowledgements
-
-- This work was supported in part by National Institutes of Health grants U54GM115677, R01LM011963, and R25MH116440. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health.
+# Please use the [Git.jl](https://github.com/JuliaVersionControl/Git.jl) package instead.