Enable ignoring tags

Currently, this action fails if tag validation fails, including if the most recent tag is not a valid SemVer version. We should add a configurable tag ignore list, probably via an action input, maybe using globs.

Start by locating the action's tag-validation logic and its input definitions. Trace how the most recent tag is selected and how validation failures are reported. Done means a configurable ignore list, including the proposed glob behavior if supported, bypasses selected invalid tags while other validation failures still fail the action.

Written by the indexing model from the issue text.