ADOPTERS.md: update Very Good Security (VGS)
ADOPTERS.md: update Very Good Security (VGS)

Add a link to the second blog post on OPA usage.

Signed-off-by: Bohdan Khablenko <9e1de578d0e6cea0bd0c03084a7c62537e1204c5@gmail.com>

open-policy-agent/opa,tsandall/opa,tsandall/opa,tsandall/opa,open-policy-agent/opa,open-policy-agent/opa,open-policy-agent/opa,tsandall/opa,tsandall/opa,tsandall/opa,open-policy-agent/opa,open-policy-agent/opa