Add aiy-board-tweaks to the manifests.

Change-Id: I814cd3e5ffb0ed97baa7eeb276befa9d85f1d78f
diff --git a/default.xml b/default.xml
index 3c0d906..8e3907f 100644
--- a/default.xml
+++ b/default.xml
@@ -70,6 +70,7 @@
     <project path="packages/aiy-board-keyring" name="aiy-board-keyring" />
     <project path="packages/aiy-board-resize2fs" name="aiy-board-resize2fs" />
     <project path="packages/aiy-board-tools" name="aiy-board-tools" />
+    <project path="packages/aiy-board-tweaks" name="aiy-board-tweaks" />
     <project path="packages/aiy-board-wlan" name="aiy-board-wlan" />
     <project path="packages/base-files" name="base-files" />
     <project path="packages/equivs" name="equivs" />