Description

Added the ability to add a retention policy to the client parameters. Mainly for v2 compatibility, which uses the retention policy to map to bucket names https://docs.influxdata.com/influxdb/v2/reference/api/influxdb-1x/dbrp/

Checklist

• Formatted code using cargo fmt --all
• Linted code using clippy
  • with reqwest feature: cargo clippy --manifest-path influxdb/Cargo.toml --all-targets --no-default-features --features use-serde,derive,reqwest-client -- -D warnings
  • with surf feature: cargo clippy --manifest-path influxdb/Cargo.toml --all-targets --no-default-features --features use-serde,derive,hyper-client -- -D warnings
• Updated README.md using cargo doc2readme -p influxdb --expand-macros
• Reviewed the diff. Did you leave any print statements or unnecessary comments?
• Any unfinished work that warrants a separate issue captured in an issue with a TODO code comment

Note: Method of chrono got deprecated which is causing some linting to fail, but that's unrelated to this PR.

Hello,

thanks for your contribution. Could you please also add tests for your feature?