Bump sbt to 1.2.3

Change-Id: Ia51946f779c2c2147fa4008fd5e153c07e224a63
diff --git a/project/build.properties b/project/build.properties
index 64317fd..0cd8b07 100644
--- a/project/build.properties
+++ b/project/build.properties
@@ -1 +1 @@
-sbt.version=0.13.15
+sbt.version=1.2.3