docs: Recommend use of dev VM for backporting
docs: Recommend use of dev VM for backporting

This will reduce chances of users using their own vagrant VMs which may
come with libraries that are incompatible with our dependencies.

Signed-off-by: Chris Tarazi <711c73f64afdce07b7e38039a96d2224209e9a6c@isovalent.com>

tklauser/cilium,michi-covalent/cilium,cilium/cilium,cilium/cilium,michi-covalent/cilium,michi-covalent/cilium,cilium/cilium,cilium/cilium,michi-covalent/cilium,tklauser/cilium,tklauser/cilium,tklauser/cilium,michi-covalent/cilium,cilium/cilium,tklauser/cilium