Add node group autoscaling policy

[c2thorn]

Fixes hashicorp/terraform-provider-google#5628

Release Note Template for Downstream PRs (will be copied)

compute: Added `autoscaling_policy` to `google_compute_node_group`

[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, 35 insertions(+))
Terraform Beta: Diff ( 3 files changed, 245 insertions(+))
TF OiCS: Diff ( 4 files changed, 126 insertions(+))
Inspec: Diff ( 5 files changed, 54 insertions(+))

[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, 36 insertions(+))
Terraform Beta: Diff ( 3 files changed, 250 insertions(+))
TF OiCS: Diff ( 4 files changed, 127 insertions(+))
Inspec: Diff ( 5 files changed, 54 insertions(+))

[slevenick]

Do these need to all be O+C? Is the autoscalingPolicy block returned from the API even if it is undefined?

[c2thorn]

Yeah the block was returning from the API in the basic test without autoscalingPolicy being set in the config, and was throwing a diff.

If the block IS defined, mode and maxNodes are required.

[slevenick]

This is a little awkwardly worded. Maybe "Minimum size of the node group. Must be an ..."

[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, 36 insertions(+))
Terraform Beta: Diff ( 3 files changed, 250 insertions(+))
TF OiCS: Diff ( 4 files changed, 127 insertions(+))
Inspec: Diff ( 5 files changed, 54 insertions(+))