Allow git commands in Vagrantfile

Due to a git CVE, we need to mark /vagrant as a "safe" directory
otherwise building containerd inside Vagrant fails with git command
failures.

Signed-off-by: Phil Estes <estesp@amazon.com>

Vagrantfile

@@ -101,6 +101,7 @@ EOF
 GOPATH=\\$HOME/go
 PATH=\\$GOPATH/bin:\\$PATH
 export GOPATH PATH
+git config --global --add safe.directory /vagrant
 EOF
     source /etc/profile.d/sh.local
     SHELL