Run buildifier

Change-Id: I9267c990ee3683783701dc9bd7f7307b703633a3
diff --git a/debian/matplotlib.BUILD b/debian/matplotlib.BUILD
index e7e9b6f..881521c 100644
--- a/debian/matplotlib.BUILD
+++ b/debian/matplotlib.BUILD
@@ -1,6 +1,9 @@
 load("@//debian:matplotlib.bzl", "build_matplotlib")
 
-build_matplotlib("3", tkinter_py_version="3.5")
+build_matplotlib(
+    "3",
+    tkinter_py_version = "3.5",
+)
 
 build_matplotlib(
     "2.7",