chore(volar): update volar package name

[sethidden]

see vuejs/language-tools#876
see https://github.com/johnsoncodehk/volar/blob/master/packages/vue-language-server/package.json#L2

[sethidden]

moved to draft since I need to:

• wait for the @volar/vue-language-server package to be published - it's published now, see https://www.npmjs.com/package/@volar/vue-language-server
• merge chore(volar): @volar/server -> @volar/vue-language-server neovim/nvim-lspconfig#1770 first it's merged :)

[williamboman]

Thank you!