TBR syncslides: upgrade to Syncbase 20

Change-Id: I3d7733a87b5ab8fe88b487b133c2f8138eccdfb1
diff --git a/dart/pubspec.lock b/dart/pubspec.lock
index a18ad55..6899ca3 100644
--- a/dart/pubspec.lock
+++ b/dart/pubspec.lock
@@ -214,7 +214,7 @@
   syncbase:
     description: syncbase
     source: hosted
-    version: "0.0.18"
+    version: "0.0.20"
   test:
     description: test
     source: hosted
diff --git a/dart/pubspec.yaml b/dart/pubspec.yaml
index efbe82b..a3c99b1 100644
--- a/dart/pubspec.yaml
+++ b/dart/pubspec.yaml
@@ -5,7 +5,7 @@
     path: "../../../../../flutter/packages/flutter"
   logging: ">=0.11.2 <0.12.0"
   mojo_services: ">=0.4.5 <0.5.0"
-  syncbase: ">=0.0.18 <0.1.0"
+  syncbase: ">=0.0.20 <0.1.0"
   v23discovery: ">=0.0.4 < 0.1.0"
   uuid: ">=0.5.0 <0.6.0"
 dev_dependencies: