Update yaml-filter submodule to the latest upstream master

jan-cerny · jan-cerny · commit 728938be6e14 · 2020-02-21T09:27:18.000+01:00
diff --git a/yaml-filter b/yaml-filter
@@ -1 +1 @@
-Subproject commit 5849f5cd5b23bb10db6cdb6153daef5a05481fb0
+Subproject commit a4a934fc814059cccd014cc64ae809dc46c97aa6
