[up] Add script to update vscode packages

[JBallin]

Could use something like this for now:

microsoft/vscode#56578 (comment):

For your scenario, there is a Extensions: Update All Extensions command that can be used. Would that help?

Is there a way to run said command (or others) from the command line?

This is slow but solved my problem:

for ext in `code --list-extensions`
  do 
    code --install-extension "$ext" 
  done

Given that this command is "slow", we may want to make it optional by adding an option in the config.