Priority: required -> Priority: optional

Change-Id: I6a0ede67165a0c306b5ffe92217265cf7e79f6d2

debian/control

diff --git a/debian/control b/debian/control
index 971eee3..790ade8 100644
--- a/debian/control
+++ b/debian/control
@@ -6,7 +6,7 @@
 
 Package: aiy-board-keyring
 Section: misc
-Priority: required
+Priority: optional
 Architecture: all
 Depends:
 Description: Public keys to verify packages for the AIY Board
\ No newline at end of file