Old dependency versions

[sobolevn]

Currently when using eslint-plugin-vue-a11y with eslint@6 there's a warning about version mismatch:

vue-eslint-parser@5.0.0 requires a peer of eslint@^5.0.0 but none is installed. You must install peer dependencies yourself.

How so?

1. eslint-plugin-vue-a11y@0.0.31 requires vue-eslint-parser@5.0
2. vue-eslint-parser@5.0 requires eslint@5
3. Boom!

How this can be solved?

• We can upgrade vue-eslint-parser@5.0 to vue-eslint-parser@7.0, it should fix the problem