Add a few simple non-POSIX bash'isms

[pombredanne]

Some common bash'ism (non-POSIX) include substrings such as ${foo:4:2} and replacement as in ${foo/bar/baz}
I have a PR in the works. Would you be open to include these?

[pombredanne]

I pushed #9 for your review

[kojiromike]

Thanks, awesome!

I've enabled the actions. I'll try to take a closer look at the code today.

[pombredanne]

Thanks! And FWIW, this will be used to support aboutcode-org/purldb#307 and in particular aboutcode-org/purldb#307 but also in the future a lightweight parsing and eval of various shell-based package manifests beyond Alpine Linux (e.g. Arch, Gentoo, MSYS2 and also autotools and a few more)

[pombredanne]

Fixed with the merger of aboutcode-org/scancode.io#9

[kojiromike]

I haven't finished automating deployment to pypi, so I'll do a manual one at some point.

[kojiromike]

0.2.0 wheel and sdist are on pypi. Please let me know how they work for you.