pull-replication plugin isn't implemented in v3.0

Remote references to the pull-replication plugin implementation
as it isn't available yet in v3.0.

Change-Id: Ic355bf349ed06545bf894e97b648d37211967466

DESIGN.md

diff --git a/DESIGN.md b/DESIGN.md
index 1bbe78f..3cdef94 100644
--- a/DESIGN.md
+++ b/DESIGN.md
@@ -192,10 +192,6 @@
 to push them again. However, someone needs to manually detect the issue in the
 replication log and get in touch with the user.
 
-The [pull-replication plugin](https://gerrit.googlesource.com/plugins/pull-replication)
-supports synchronous replication and has the structure to perform also the
-asynchronous variant in the future.
-
 ## History and maturity level of the multi-site plugin
 
 This plugin expands upon the excellent work on the high-availability plugin,
@@ -254,8 +250,8 @@
 The current limitations of Stage #9 are:
 
 - **Limited supports for many sites**:
-  One could, potentially, support a very high number of sites, but the pull-replication
-  logic to all sites could have a serious consequence in the overall perceived latency.
+  One could, potentially, support a very high number of sites, but replication lag
+  to all sites could have a serious consequence in the overall perceived latency.
   Having to deal with a very high number of site requires the implementation of a quorum on
   all the nodes available for replication.
 
@@ -652,6 +648,9 @@
 - Implement more global-refdb storage layers (e.g. TiKV) and more cloud-native
   message brokers (e.g. NATS)
 
+- Implement a synchronous pull-replication plugin for triggering the replication
+  logic on all the other sites, based on Git protocol v2 upload-pack.
+
 - Implement a quorum-based policy for accepting or rejecting changes in the pull-replication
   plugin