v0.10.0

I imagine this as the last minor version release before v1.0.0. JILL functionality is becoming quite stable and I'm very satisfied with this, thus probably there won't be any major feature changes in the future. I rewrite the entire README; hopefully, it gives a better overview of all the features of jill.

Enhancements:

• The timeout for jill install latest is now set to 30 seconds. Hopefully, this solves the network issues like #82. (#89) (@johnnychen94)
• As a side-effect of #89, jill now supports tarball format .tar.gz for Windows and macOS systems. Yet we still use .dmg and .exe for these systems because they're self-signed. (#89)(@johnnychen94)

Features:

• command jill switch allows you to switch what version julia points to. (#92) (@johnnychen94)
• command jill list shows every julia command(symlink) and the version it points to. (#90) (@johnnychen94)
• For Julia maintainers, jill install <version>+<hash> is a simple interface to fetch specific CI build artifacts in the Julialang/julia repository. For instance, jill install 1.8.0+cc4be25c installs the CI artifact for cc4be25c commit into julia-dev. (#89)(@johnnychen94)