Add python3 to the build scripts

Several packages have been upgraded to use python3 in the
latest yocto version, therefore the build scripts needs to
incorporate that dependency.

Change-Id: I300295f0434f690c795ce863f159ab9980af1a48
Signed-off-by: Saqib Khan <khansa@us.ibm.com>
diff --git a/qemu-build.sh b/qemu-build.sh
index a80d4e7..044632b 100755
--- a/qemu-build.sh
+++ b/qemu-build.sh
@@ -28,7 +28,7 @@
 	libpixman-1-dev \
 	libglib2.0-dev \
 	libfdt-dev \
-	make python-yaml gcc libc6-dev
+	make python-yaml python3-yaml gcc libc6-dev
 
 RUN grep -q ${GROUPS} /etc/group || groupadd -g ${GROUPS} ${USER}
 RUN grep -q ${UID} /etc/passwd || useradd -d ${HOME} -m -u ${UID} -g ${GROUPS} ${USER}