v0.3.21 raised MSRV to 1.47.0

[stephank]

The readme lists MSRV 1.30, but patch release 0.3.21 raised that to 1.47.0 by using Result::as_deref. I have a project that uses 1.46, and don't mind if it needs to be raised, just thought I'd check first. Here's the error:

error[E0658]: use of unstable library feature 'inner_deref'
   --> /home/runner/.cargo/registry/src/github.com-1ecc6299db9ec823/pkg-config-0.3.21/src/lib.rs:163:53
    |
163 |                         let crate_name = crate_name.as_deref().unwrap_or("sys");
    |                                                     ^^^^^^^^
    |
    = note: see issue #50264 <https://github.com/rust-lang/rust/issues/50264> for more information

[sdroege]

Thanks, should really add CI for this. As this is the only usage and not really complicated to do otherwise, let's do that instead of raising the MSRV :)

Do you want to provide a PR? Otherwise I'll take care of this later.

[stephank]

I created #125. Is Travis broken? I could also try create a PR for GitHub Actions, if that's preferred.

[Enselic]

I just independently created a basic GitHub Actions port, found here: #126

It fails because of this MSRV bug on 1.30, and does not port deploy to gh-pages. Feel free to reuse or start from scratch.

[sdroege]

I created #125. Is Travis broken? I could also try create a PR for GitHub Actions, if that's preferred.

Yes Travis is unfortunately broken.