Add sepolicy for com.android.compos

This is to unblock the apex setup.

There is only a system_file in the context, but we might need more
specific ones later.

Bug: 186126404
Test: m

Change-Id: Icf713c9bb92e7f7402c0b45bd0f1b06e9cb35d2b
diff --git a/apex/com.android.compos-file_contexts b/apex/com.android.compos-file_contexts
new file mode 100644
index 0000000..83b4b58
--- /dev/null
+++ b/apex/com.android.compos-file_contexts
@@ -0,0 +1 @@
+(/.*)?                   u:object_r:system_file:s0