Bump minimal version of pkg-config? (build error)

[johalun]

I have an app that uses the cursive crate which has this crate as dependency. If I run (on my app)

rustup override set nightly
cargo update -Zminimal-versions
cargo check --all-targets

I get build failure in pkg-config 0.3.0.

I think the minimum version for pkg-config needs to be bumped to one that's not broken.