b/143703072: Add version number to cache silo
b/143703072: Add version number to cache silo

In case of widespread cache corruption, we can manually increment the version number instead of filing a ticket with RBE.

Change-Id: Ie96a2f8c6d43b73a6d5b298cf277d84cc8445357
Signed-off-by: Teju Nareddy <86db88dbc1cba831353c118b8473a42f6361b545@google.com>

GoogleCloudPlatform/esp-v2,GoogleCloudPlatform/esp-v2,GoogleCloudPlatform/esp-v2,GoogleCloudPlatform/esp-v2,GoogleCloudPlatform/esp-v2