Duplicate rules should be allowed

[moltar]

I think duplicate rules should be allowed.

The use case is in a monorepo. Rules can be assembled from different locations (inputs) and provide different configuration options.

They are disallowed here:

secretlint/packages/@secretlint/core/src/RunningEvents.ts

Lines 65 to 71 in 9a68dfc

	if (registerSet.has(descriptorRule.id)) {
	// TODO: more trivial implementation
	throw new Error(`rule.id:${descriptorRule.id} is already registered.
	Duplicated rule.id is something wrong in .secretlintrc.
	`);
	}

[azu]

I think that there are not many useful cases in the current situation where rules can not be set for each file path like #105
So, I thought that most of the cases were set incorrectly, so I made it an error.

[moltar]

Yes, I think #105 can cover this use case in another way.