feat: add type for "rollup-plugin-buble"

[Kocal]

This PR add typings for rollup-plugin-buble.

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• Test the change in your own code. (Compile and run.)
• Add or edit tests to reflect the change. (Run with npm test.)
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• Run npm run lint package-name (or tsc if no tslint.json is present).

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If adding a new definition:

• The package does not already provide its own types, or cannot have its .d.ts files generated via --declaration
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[typescript-bot]

@Kocal Thank you for submitting this PR!

Because this is a new definition, a DefinitelyTyped maintainer will be reviewing this PR in the next few days once the Travis CI build passes.

In the meantime, if the build fails or a merge conflict occurs, I'll let you know. Have a nice day!

[typescript-bot]

I just published @types/rollup-plugin-buble@0.19.0 to npm.