xds spec: add section about PGV annotations (#21517)
xds spec: add section about PGV annotations (#21517)

Describe use of PGV annotations in xDS.

Signed-off-by: Mark D. Roth <f8bfa21f32be4966fb4ed6a329fe0dc16bf1b1c7@google.com>
envoyproxy/envoy,envoyproxy/envoy,envoyproxy/envoy,envoyproxy/envoy,envoyproxy/envoy,envoyproxy/envoy,envoyproxy/envoy,envoyproxy/envoy,envoyproxy/envoy,envoyproxy/envoy,envoyproxy/envoy,envoyproxy/envoy