chore: release v0.21.0

[github-actions]

🤖 New release

• octocrab: 0.20.0 -> 0.21.0 (⚠️ API breaking changes)

⚠️ octocrab breaking changes

--- failure enum_variant_missing: pub enum variant removed or renamed ---

Description:
A publicly-visible enum has at least one variant that is no longer available under its prior name. It may have been renamed or removed entirely.
        ref: https://doc.rust-lang.org/cargo/reference/semver.html#item-remove
       impl: https://github.com/obi1kenobi/cargo-semver-check/tree/v0.20.0/src/lints/enum_variant_missing.ron

Failed in:
  variant Error::Url, previously in file /tmp/.tmpzMQIjV/octocrab/src/error.rs:55

--- failure inherent_method_missing: pub method removed or renamed ---

Description:
A publicly-visible method or associated fn is no longer available under its prior name. It may have been renamed or removed entirely.
        ref: https://doc.rust-lang.org/cargo/reference/semver.html#item-remove
       impl: https://github.com/obi1kenobi/cargo-semver-check/tree/v0.20.0/src/lints/inherent_method_missing.ron

Failed in:
  OctocrabBuilder::base_url, previously in file /tmp/.tmpzMQIjV/octocrab/src/lib.rs:499

Changelog

0.21.0 - 2023-04-29

Other

• Add an example showing gist creation (examples: Add an example showing gist creation #329)
• Use CommitAuthor for Commit.author (Use CommitAuthor for Commit.author #353)
• Create release-plz.toml
• Sort deps in cargo.toml (Sort deps in cargo.toml #352)
• Enable rustls(and use as default client) (Enable rustls(and use as default client) #351)
• (ci) update release-plz version (chore(ci): update release-plz version #350)
• Add missing pub to struct ListCheckRuns 😅 (models: Add missing pub to struct ListCheckRuns 😅 #347)
• Add Checks API skeleton (Add Checks API skeleton #345)
• cargo fmt (ci: cargo fmt #343)
• Remove reqwest (Remove reqwest #342)

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