Add EXTERNAL_MANAGED as load_balancing_scheme for google_compute_backend_service

[AlexanderEllis]

This adds EXTERNAL_MANAGED as a load_balancing_scheme option for the backend service resource. It's one of the parts needed to add support for the new Global External HTTP(S) Load Balancer (the other part will require DCL changes to the global forwarding rule).

part of hashicorp/terraform-provider-google#10858

Tested with make testacc TEST=./google-beta TESTARGS='-run=TestAccComputeBackendService_backendServiceExternalManagedExample'

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Release Note Template for Downstream PRs (will be copied)

compute: Added EXTERNAL_MANAGED as option for load_balancing_scheme in google_compute_backend_service resource

[modular-magician]

Hello! I am a robot who works on Magic Modules PRs.

I have detected that you are a community contributor, so your PR will be assigned to someone with a commit-bit on this repo for initial review.

Thanks for your contribution! A human will be with you soon.

@shuyama1, please review this PR or find an appropriate assignee.

[modular-magician]

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

Diff report:

Terraform GA: Diff ( 3 files changed, 49 insertions(+), 25 deletions(-))
Terraform Beta: Diff ( 4 files changed, 101 insertions(+), 34 deletions(-))
TF OiCS: Diff ( 4 files changed, 115 insertions(+))

[shuyama1]

/gcbrun

[modular-magician]

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

Diff report:

Terraform GA: Diff ( 2 files changed, 27 insertions(+), 3 deletions(-))
Terraform Beta: Diff ( 4 files changed, 92 insertions(+), 25 deletions(-))
TF OiCS: Diff ( 4 files changed, 115 insertions(+))

[modular-magician]

I have triggered VCR tests in RECORDING mode for the following tests that failed during VCR: TestAccDatasourceGoogleServiceNetworkingPeeredDnsDomain_basic|TestAccApigeeEnvironmentIamBindingGenerated|TestAccApigeeEnvironmentIamMemberGenerated|TestAccApigeeEnvironmentIamPolicyGenerated|TestAccComputeBackendService_backendServiceExternalManagedExample|TestAccContainerNodePool_withInvalidUpgradeSettings|TestAccPrivatecaCertificateAuthority_privatecaCertificateAuthoritySubordinateExample|TestAccPrivatecaCertificate_privatecaCertificateConfigExample|TestAccPrivatecaCertificate_privatecaCertificateNoAuthorityExample You can view the result here: https://ci-oss.hashicorp.engineering/viewQueued.html?itemId=241056

[shuyama1]

LGTM and tests passed! Thank you for your contribution!

[AlexanderEllis]

Thanks!