v1 api: link to deprecation schedule (#553)
v1 api: link to deprecation schedule (#553)

Signed-off-by: Matt Klein <684e4e870ef5a243d6d0345280f09d95db603639@lyft.com>
jrajahalme/envoy-api,lyft/envoy-api,lyft/envoy-api,jrajahalme/envoy-api,jrajahalme/envoy-api,lyft/envoy-api,jrajahalme/envoy-api