Rate-limiting check doesn't respect "--no-publish"

[Michael-F-Bryan]

When trying to publish the first version of a large workspace, I ran into the error message introduced in #545.

My plan was to do a cargo release --no-publish to bump all the version numbers then publish manually to avoid rate limits, but it seems like verify_rate_limit() gets called even when you won't push to crates.io.

$ cargo release 0.2.0-rc.1 --execute --no-publish
error: attempting to publish 18 new crates which is above the crates.io rate limit