Values:
TYPE_UNSPECIFIED (0):
Encryption type was not specified, though
data at rest remains encrypted.
GOOGLE_DEFAULT_ENCRYPTION (1):
The data is encrypted at rest with a key that
is fully managed by Google. No key version or
status will be populated. This is the default
state.
CUSTOMER_MANAGED_ENCRYPTION (2):
The data is encrypted at rest with a key that is managed by
the customer. The active version of the key.
kms_key_version will be populated, and
encryption_status may be populated.
