feat(language-server): add serverInfo to initialized result

[kada49]

The Language Server Specification added a serverInfo parameter in version 3.15.0 (01/14/2020).

How I implemented it seems a little hacky to me, but I couldn't find a better way to do it. Improvements are welcome!

Old

- vue_ls (id: 1)
  - Version: ? (no serverInfo.version response)
  - Root directory: ~/Desktop/website
  - Command: { "vue-language-server", "--stdio" }
  - Settings: {}
  - Attached buffers: 1

New

- vue_ls (id: 1)
  - Version: 3.1.4
  - Root directory: ~/Desktop/website
  - Command: { "/home/kada49/Desktop/language-tools/packages/language-server/bin/vue-language-server.js", "--stdio" }
  - Settings: {}
  - Attached buffers: 1

Note: the new command is changed because of me using a different build for the new one

[pkg-pr-new]

Open in StackBlitz

vue-component-meta

npm i https://pkg.pr.new/vuejs/language-tools/vue-component-meta@5767

vue-component-type-helpers

npm i https://pkg.pr.new/vuejs/language-tools/vue-component-type-helpers@5767

@vue/language-core

npm i https://pkg.pr.new/vuejs/language-tools/@vue/language-core@5767

@vue/language-plugin-pug

npm i https://pkg.pr.new/vuejs/language-tools/@vue/language-plugin-pug@5767

@vue/language-server

npm i https://pkg.pr.new/vuejs/language-tools/@vue/language-server@5767

@vue/language-service

npm i https://pkg.pr.new/vuejs/language-tools/@vue/language-service@5767

vue-tsc

npm i https://pkg.pr.new/vuejs/language-tools/vue-tsc@5767

@vue/typescript-plugin

npm i https://pkg.pr.new/vuejs/language-tools/@vue/typescript-plugin@5767

commit: a105ae2

[KazariEX]

@johnsoncodehk Should we add a fourth parameter to the initialize method to pass this information?