[infra] Add wildcard OWNERS

This is a requirement to enforce code review.

Bug: skia:12124
Change-Id: Ia35c5fec148329625daaffecec60116c291633ed
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/443637
Reviewed-by: Ravi Mistry <rmistry@google.com>
diff --git a/OWNERS b/OWNERS
new file mode 100644
index 0000000..72e8ffc
--- /dev/null
+++ b/OWNERS
@@ -0,0 +1 @@
+*