mojo/syncbase: Upgrade to mojov7 and version 30

As title, this puts us at mojo 0.2.15

MultiPart: 2/3

Change-Id: I8e0e68f0778865799d4e231d00e0bbff49f169a7
diff --git a/pubspec.yaml b/pubspec.yaml
index ee7ace0..5bd3863 100644
--- a/pubspec.yaml
+++ b/pubspec.yaml
@@ -2,9 +2,9 @@
 description: Syncbase is a storage system for developers that makes it easy to synchronize app data between devices. It works even when devices are not connected to the Internet.
 homepage: https://github.com/vanadium/mojo.syncbase
 name: syncbase
-version: 0.0.29
+version: 0.0.30
 dependencies:
-  mojo_sdk: 0.2.11
+  mojo_sdk: 0.2.15
 dev_dependencies:
   dart_style: any
   test: any