Steps to publish a new clippy version

1. cargo test.

• Bump package.version in ./Cargo.toml (no need to manually bump dependencies.clippy_lints.version).
• Run ./util/update_lints.py.
• Write a changelog entry.
• Commit ./Cargo.toml, ./clippy_lints/Cargo.toml and ./CHANGELOG.md.
• git push
• Wait for Travis's approval.
• Merge.
• cargo publish in ./clippy_clints.
• cargo publish in the root directory.
• git pull.
• git tag -s v0.0.X.
• git push --tags.