Include "espree" dependency in package.json

[DEVTomatoCake]

espree is required by this package (at least when using the flat config, according to the file name), but not included as dependency directly. This can cause errors if espree is not installed from other packages already. https://github.com/BenoitZugmeyer/eslint-plugin-html/blob/9e91f974f5c19ec35169789facbc361d9ea41c5a/src/verifyWithFlatConfigPatch.js#L164

This issue apparently occurred after updating eslint-plugin-html to v53, and doesn't occur on v52. I'm unable to reproduce this locally, however as espree is directly used in this package it always should be included in the package.json.