Add checking if cloud shell env is trusted (#27)
Add checking if cloud shell env is trusted (#27)

Shouldn't be needed once the image is trusted (minus test/dev images),
but still adding as a safeguard otherwise we print a cryptic error.
It slows everything by ~1s but it's better than a cryptic error.

Signed-off-by: Ahmet Alp Balkan <c786c8527fd6be7431bb94ca48b6f76cc06787cc@google.com>
GoogleCloudPlatform/cloud-run-button,GoogleCloudPlatform/cloud-run-button,GoogleCloudPlatform/cloud-run-button,GoogleCloudPlatform/cloud-run-button