publish --dry-run validate more Cargo.toml keys

[jordy25519]

Problem

some validations failing after passing --dry-run:

• keywords max limit is 5
• categories must be from a subset supported slugs

I assumed --dry-run success meant validation passes and the crate will upload successfully

painful to rerun build several times to encounter these

Proposed Solution

• hard lints/error for keywords count > 5 in --dry-run mode
• validate categories from subset of known slugs or network request to update the list

Notes

cargo 1.81.0 (2dbb1af80 2024-08-20)

[weihanglo]

Hi! Thank you for the report! This seems to be a duplicate of #2098, #3662, #4300, #4377, #14249, #14426. Among them, #4377 is the main tracking issue of it, so closing in favor of that.

Note that the limitations are set by a single registry (crates.io), while Cargo needs to support different registries.