Feat: Release-as should always take effect when merged to main

**Is your feature request related to a problem? Please describe.**
Most of my monorepo's build config lives at the root level. If I make a change here that impacts a package no committed files within the package's root change. Therefore release please does not create a release for the package. So far this makes sense: how _could_ release please know.

I added `"release-as": "1.2.3"` to the package override in release-please-config.json to - as I expected - force the package to be released when my PR was merged. To my dismay, this only forces a release at that version number if there were committed changes within the package directory.

There does not appear to be away to force a release of a package in a monorepo unless there are changes to committed files within the package directory. This does not support sharing build tooling between packages very well.

**Describe the solution you'd like**
Either
1. `release-as`, when added to a package config, forces a release on the next push to main
2. An additional option, `forceReleaseWithoutRelevantCommit: true` (or similar) to force a package release without any commits in the relevant directory

**Additional context**
Relevant PR https://github.com/wheresrhys/fetch-mock/pull/771