Bump supported cpython version to 3.14 for testing #12396

Annotations

5 errors and 1 warning

`cargo clippy --no-default-features --all-targets --workspace -- --deny=warnings` failed

`cargo clippy --no-default-features --features=abi3 --all-targets --workspace -- --deny=warnings` failed

`cargo clippy --features=full,multiple-pymethods,jiff-01 --all-targets --workspace -- --deny=warnings` failed

`cargo clippy --features=abi3,full,multiple-pymethods,jiff-01 --all-targets --workspace -- --deny=warnings` failed

Process completed with exit code 1.

ubuntu-latest pipelines will use ubuntu-24.04 soon. For more details, see https://github.com/actions/runner-images/issues/10636