docs/README.md: add note about Hugo version mismatch errors (#4453)
docs/README.md: add note about Hugo version mismatch errors (#4453)

Signed-off-by: Omri Gazitt <198ca66d5b94ba3bec9bf9ccbeec4d9d6578488f@gmail.com>
tsandall/opa,tsandall/opa,open-policy-agent/opa,tsandall/opa,open-policy-agent/opa,open-policy-agent/opa,open-policy-agent/opa,tsandall/opa,open-policy-agent/opa,tsandall/opa,open-policy-agent/opa,tsandall/opa