Make lint fails with errors

[f5yacobucci]

Running make lint on the main branch generates errors.

Steps to reproduce the behavior:

1. git clone [ngx-rust project]
2. make lint

Expected behavior
Ideally, make lint should complete clean without warnings (-D warnings) or errors. But make lint (cargo clippy) must complete without errors.

Your environment

• Version of the repo - 4aa2e35
• Version of ngx-rust - 0.3.0-beta
• Version of Rust - 1.71.0-nightly
• Version of NGINX (and all dependencies if modified) - N/A
• OS and distribution - Ubuntu 22.04.2 LTS
• Details about containerization, virtualization, or physical environment - N/A

Additional context
Suggested tasks:

• Propose lint (clippy.toml) configuration for consistency
• Add git action to run lint appropriately (build / review)
• Run strict checks (-D warnings)
• Make main branch clean and free of error

[ivanitskiy]

done via #46