package/python-matplotlib: add Pillow dependency

Pillow is mandatory dependency since version 3.3.0.

Signed-off-by: Witold Lipieta <witold.lipieta@thaumatec.com>
Signed-off-by: Arnout Vandecappelle <arnout@mind.be>

package/python-matplotlib/Config.in

@@ -11,6 +11,7 @@ config BR2_PACKAGE_PYTHON_MATPLOTLIB
 	select BR2_PACKAGE_PYTHON_DATEUTIL # runtime
 	select BR2_PACKAGE_PYTHON_KIWISOLVER # runtime
 	select BR2_PACKAGE_PYTHON_NUMPY # runtime
+	select BR2_PACKAGE_PYTHON_PILLOW # runtime
 	select BR2_PACKAGE_PYTHON_PYPARSING # runtime
 	select BR2_PACKAGE_PYTHON3_ZLIB # runtime
 	select BR2_PACKAGE_QHULL