Link to example App.jl file in docs/src/app.md is broken

[josephmckinsey]

The link at

PackageCompiler.jl/docs/src/apps.md

Line 203 in 1c35331

is [used in the source](https://github.com/JuliaLang/PackageCompiler.jl/blob/d722a3d91abe328ebd239e2f45660be35263ebe1/examples/MyApp/src/MyApp.jl#L7-L8).

is broken

The example app uses the artifact system to depend on a very simple toy binary
that does some simple arithmetic. It is instructive to see how the [artifact
file](https://github.com/JuliaLang/PackageCompiler.jl/blob/master/examples/MyApp/Artifacts.toml)
is [used in the source](https://github.com/JuliaLang/PackageCompiler.jl/blob/d722a3d91abe328ebd239e2f45660be35263ebe1/examples/MyApp/src/MyApp.jl#L7-L8).

What version is this supposed to point to?