v0.2.20 broke compatibility with older Rust versions

[RazrFalcon]

Rust 1.18 can build v0.2.19 but not v0.2.21 Does it considered as a braking change?

[KodrAus]

Hi @RazrFalcon 👋

It looks like we're just targeting the latest stable for getopts so I don't think we're considering bumps in the minimum supported Rust version as breaking changes.

[RazrFalcon]

I see, thanks.

[commonquail]

It looks like we're just targeting the latest stable for getopts

Because 5148159 undid #63 and then 15fd785 pushed MSRV all the way from 1.18 to 1.27, and then v0.2.21 raised it further to 1.31.