Install python3-gst-1.0 by default.

Change-Id: Iaca24a742fc6f5c07c1c0e6f81031931f9496e81
diff --git a/preamble.mk b/preamble.mk
index 1748138..77ade50 100644
--- a/preamble.mk
+++ b/preamble.mk
@@ -115,6 +115,7 @@
 	python \
 	python-minimal \
 	python2.7 \
+	python3-gst-1.0 \
 	python3-jwt \
 	python3-numpy \
 	python3-pip \