.gitconfig includeif not available inside container

• VSCode Version:
  Version: 1.41.0-insider
  Commit: 599c076d91be1374cf51004cec610f3bcaf4c9cd
  Date: 2019-11-22T07:19:06.796Z
  Electron: 6.1.5
  Chrome: 76.0.3809.146
  Node.js: 12.4.0
  V8: 7.6.303.31-electron.0

• Local OS Version:
  OS: Darwin x64 18.7.0

• Remote OS Version:
  Debian 9 (mcr.microsoft.com/powershell)

• Remote Extension/Connection Type: Docker

Steps to Reproduce:

1. includeif in gitconfig is not honoured inside the developement container.

Local .gitconfig contains

[includeIf "gitdir/i:~/git/gitpersonal/"]
	path = ~/.gitconfig-personal

git config --list --show-origin

Local

file:/Users/brett.miller/.gitconfig     user.name=Brett Miller
file:/Users/brett.miller/.gitconfig     user.email=brett.miller@org.com
file:/Users/brett.miller/.gitconfig     includeif.gitdir/i:~/git/gitpersonal/.path=~/.gitconfig-personal
file:/Users/brett.miller/.gitconfig-personal    user.name=Brett Miller
file:/Users/brett.miller/.gitconfig-personal    user.email=brett@millerb.co.uk
file:/Users/brett.miller/.gitconfig     core.editor=code-insiders --wait

Devcontainer

file:/root/.gitconfig   user.name=Brett Miller
file:/root/.gitconfig   user.email=brett.miller@org.com
file:/root/.gitconfig   includeif.gitdir/i:~/git/gitpersonal/.path=~/.gitconfig-personal
file:/root/.gitconfig   core.editor=code-insiders --wait

Seen #1811 but didn't think it was the same thing.