Error in Docker build - GPG error: http://packages.cloud.google.com/apt gcsfuse-bionic InRelease: The following signatures couldn't be verified because the public key is not available

[Calli Rogers]

Following the README at mlops-on-gcp/examples/mlops-env-on-gcp/creating-notebook-instance/README.md step by step results in below error:

W: GPG error: http://packages.cloud.google.com/apt gcsfuse-bionic InRelease: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY FEEA9169307EA071 NO_PUBKEY 8B57C5C2836F4BEB
E: The repository 'http://packages.cloud.google.com/apt gcsfuse-bionic InRelease' is not signed.
W: GPG error: http://packages.cloud.google.com/apt cloud-sdk-bionic InRelease: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY FEEA9169307EA071 NO_PUBKEY 8B57C5C2836F4BEB
E: The repository 'http://packages.cloud.google.com/apt cloud-sdk-bionic InRelease' is not signed.
The command '/bin/sh -c apt-get update -y && apt-get -y install kubectl' returned a non-zero code: 100
ERROR
ERROR: build step 0 "gcr.io/cloud-builders/docker" failed: step exited with non-zero status: 100

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ERROR: (gcloud.builds.submit) build 9113de9f-5276-4960-8a47-994431acdf5c completed with status "FAILURE"
crogers@mbp-crogers lab-workspace % nano Dockerfile 
crogers@mbp-crogers lab-workspace % gcloud builds submit --timeout 15m --tag ${IMAGE_URI} .
Creating temporary tarball archive of 3 file(s) totalling 3.0 KiB before compression.
Uploading tarball of [.] to [gs://PROJECT-REDACTED_cloudbuild/source/1623070913.599017-56c228c79bb6488d876045d2e8ceb9bc.tgz]
Created [https://cloudbuild.googleapis.com/v1/projects/PROJECT-REDACTED/locations/global/builds/9571dabd-6d86-4139-9adf-960de21e3434].
Logs are available at [https://console.cloud.google.com/cloud-build/builds/9571dabd-6d86-4139-9adf-960de21e3434?project=169360861282].```


Work around is to add `RUN curl https://packages.cloud.google.com/apt/doc/apt-key.gpg | apt-key add - ` as the second line of the Dockerfile