document release workflow

[williballenthin]

• [ ] bump ./flirt/Cargo.toml::package::version
• [ ] bump ./core/Cargo.toml::package::version
• [ ] update ./core/Cargo.toml::dependencies::lancelot-flirt::version
• [ ] bump ./pylancelot/Cargo.toml::package::version
• [ ] bump ./bin/Cargo.toml::package::version
• [ ] update ./bin/Cargo.toml::dependencies::lancelot::version
• [ ] commit & push
• [ ] release in gh

[williballenthin]

see bump-versions.sh in 2b1faba

bash .github/workflows/bump-version.sh 0.3.2