examples: replace structopt with pico-args

[tamird]

See TeXitoi/structopt#525.

Currently codespan-reporting is the most downloaded dependent of
structopt: https://crates.io/crates/structopt/reverse_dependencies.

[tamird]

@Johann150 perhaps? Unclear if this repository is maintained.

[Johann150]

Please check your code formatting (or run cargo fmt), as indicated by the CI. You would probably also want to rebase on the master branch, since there unfortunately was some broken CI.

There also seems to be an issue with the minimum supported Rust version so CI will probably not completely pass still, but I don't feel qualified to change that. I'm just a collaborator, not a maintainer of this package.

[tamird]

Both issues should be fixed now. Could you trigger another run?

[tamird]

One more attempt please! Should be fixed now. Implementing "possible values" on foreign types is a bit clumsier now.

[tamird]

Looks like we'd need to bump MSRV to 1.56 fro 1.46 to allow this to land. See description in d-e-s-o/test-log@9619698.

[tamird]

Would you mind allowing CI to run again?

[tamird]

Sadly have to bump further to 1.60. Could you run CI again?

[tamird]

Needed to update the arguments to cargo update. Another run, please!

[tamird]

Once more please! Need 1.61.

[tamird]

@Johann150 this is finally green. If you are not able to approve this MSRV bump, can you ping someone who is?

[Johann150]

I don't think it makes sense to raise the MSRV for the entire library just because one of the examples requires it. It would probably be a better idea to use another parsing framework, e.g. pico-args for this, or alternatively remove command line parsing from the example files and documentation code examples.

[tamird]

Done.

I added another commit to remove ColorArg, but I can withdraw it if you prefer.

[tamird]

@Johann150 can you please run CI?

[tamird]

@Johann150 ping.

[tamird]

@Johann150 could you have a look please?

[tamird]

@Johann150 ping.

[kaleidawave]

Have moved pico-args to dev-dependencies. Therefore it should NOT introduce breakages for those who use this library.

I have checked and all the examples work and as intended (on latest Rust). The CI needs improving (and it is raising issues on dependencies, not this project) and as this does not touch library code it should be fine, for merging!

Thanks for updating from struct-opt which has been in maintenance for nearly 3 years. If you have any other changes, feel free to open a follow up PR.