chore(gitignore): add .vscode

[leon-win]

Description

Add .vscode item to .gitignore file.

Motivation

The .vscode folder contains settings for a widely used editor Visual Studio Code. To allow users to save their workspace settings, we must add .vscode to the .gitignore file.

For example my settings (enables auto formatting markdown files with installed markdownlint extension):

{
  "editor.codeActionsOnSave": {
    "source.fixAll.markdownlint": true
  },
  "[markdown]": {
    "editor.formatOnSave": true
  }
}