Branch to allow 1.3 to be installable

[ericphanson]

What do you think of this @giordano? An empty package with version number v0.0.1 that allows Julia 1.3+, so that it can be used in RegistryCI, xref https://github.com/JuliaRegistries/RegistryCI.jl/pull/492#issuecomment-1404355908.

If you're OK with that version existing, I'd register from this branch and we'd have that dummy version in the registry for RegistryCI to use on pre-1.6.

[ericphanson]

It is not easy to actually support 1.3 because RegistryInstances requires 1.6+

[giordano]

Uhm, ok

[ericphanson]

branch is registered