release 0.5.0 about twitch_api

[Emilgardis]

version 0.5.0-alpha.3 released, this version now depends on tokio = 1.0

[Emilgardis]

oauth2 4 is out. Want to work out some minor stuff before release

[Emilgardis]

v0.5.0-beta.1 released

a real release will follow soon as long as no issues are found

[Emilgardis]

Have to publish v0.5.0-beta.2 as docs.rs could not properly render docs

#117

[INFO] [stderr] error[E0599]: no function or associated item named `new` found for struct `surf::Client` in the current scope
[INFO] [stderr]   --> /opt/rustwide/cargo-home/registry/src/github.com-1ecc6299db9ec823/twitch_oauth2-0.5.0-beta.1/src/client.rs:37:40
[INFO] [stderr]    |
[INFO] [stderr] 37 | ...   let client = surf::Client::new(); // If this fails to compile, please use feature `surf_client_curl` or specify surf with a client ...
[INFO] [stderr]    |                                  ^^^ function or associated item not found in `surf::Client`
[INFO] [stderr] 
[INFO] [stderr] error: aborting due to previous error
[INFO] [stderr] 
[INFO] [stderr] For more information about this error, try `rustc --explain E0599`.
[INFO] [stderr] error: could not compile `twitch_oauth2`
[INFO] [stderr] 
[INFO] [stderr] To learn more, run the command again with --verbose.