Upstream flex template update

[slevenick]

Upstreams: hashicorp/terraform-provider-google-beta#3069

If this PR is for Terraform, I acknowledge that I have:

• Searched through the issue tracker for an open issue that this either resolves or contributes to, commented on it to claim it, and written "fixes {url}" or "part of {url}" in this PR description. If there were no relevant open issues, I opened one and commented that I would like to work on it (not necessary for very small changes).
• Generated Terraform, and ran make test and make lint to ensure it passes unit and linter tests.
• Ensured that all new fields I added that can be set by a user appear in at least one example (for generated resources) or third_party test (for handwritten resources or update tests).
• Ran relevant acceptance tests (If the acceptance tests do not yet pass or you are unable to run them, please let your reviewer know).
• Read the Release Notes Guide before writing my release note below.

Release Note Template for Downstream PRs (will be copied)

dataflow: enabled updates for `google_dataflow_flex_template_job`

[modular-magician]

Hi! I'm the modular magician. Your PR generated some diffs in downstreams - here they are.

Diff report:

Terraform GA: Diff ( 1 file changed, 2 insertions(+), 2 deletions(-))
Terraform Beta: Diff ( 4 files changed, 181 insertions(+), 122 deletions(-))

[modular-magician]

I have triggered VCR tests based on this PR's diffs. See the results here: "https://ci-oss.hashicorp.engineering/viewQueued.html?itemId=181448"

[modular-magician]

I have triggered VCR tests in RECORDING mode for the following tests that failed during VCR: TestAccCloudRunDomainMapping_foregroundDeletion|TestAccComputeForwardingRule_ip You can view the result here: "https://ci-oss.hashicorp.engineering/viewQueued.html?itemId=181465"

[modular-magician]

Tests failed during RECORDING mode: TestAccCloudRunDomainMapping_foregroundDeletion Please fix these to complete your PR

[andremarianiello]

Anything I can do to help usher this along? Do you know what is causing the CI failure?

[modular-magician]

Hi! I'm the modular magician. Your PR generated some diffs in downstreams - here they are.

Diff report:

Terraform GA: Diff ( 1 file changed, 2 insertions(+), 4 deletions(-))
Terraform Beta: Diff ( 3 files changed, 179 insertions(+), 123 deletions(-))

[modular-magician]

I have triggered VCR tests based on this PR's diffs. See the results here: "https://ci-oss.hashicorp.engineering/viewQueued.html?itemId=182556"

[modular-magician]

I have triggered VCR tests in RECORDING mode for the following tests that failed during VCR: TestAccCloudRunDomainMapping_foregroundDeletion You can view the result here: "https://ci-oss.hashicorp.engineering/viewQueued.html?itemId=182561"

[modular-magician]

Tests failed during RECORDING mode: TestAccCloudRunDomainMapping_foregroundDeletion Please fix these to complete your PR

[c2thorn]

Fairly similar to the resource_dataflow_job.go equivalent. LGTM