Remove or replace "*" in activationEvents

[hmnd]

Problem
Currently, this extension runs on any project, even if that project doesn't use openapi. This unnecessarily adds ~950ms to activation time in some of my larger projects, even though they don't use openapi.

Solution
I know this extension contributes validation schemas and has some commands, but I'm not sure of the full scope of what it does.
If this extension doesn't do anything beyond the validation schemas and commands, I believe the "*" event in package.json's acitvationEvents can be removed entirely.
Otherwise, it could be replaced with specific events, similar to "workspaceContains:**/*swagger.json".