Support compute reservation resize

[megan07]

Fixes hashicorp/terraform-provider-google#4937

Release Note Template for Downstream PRs (will be copied)

compute: added ability to resize `google_compute_reservation`

[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, 115 insertions(+), 2 deletions(-))
Terraform Beta: Diff ( 3 files changed, 115 insertions(+), 2 deletions(-))
Ansible: Diff ( 1 file changed, 18 insertions(+), 5 deletions(-))

[chrisst]

Looking at the downstream this api is following the update with computeOperationWaitTime as though the API returned an operation object. But the API docs don't make it sound like this API supports operations. Also the API has invented it's own error output, which makes me think that they might return an error in a way we won't capture correctly at this time. Can you confirm that bad input (-1 count? stupid large count) returns an actionable error to the user?

[chrisst]

What happens if you update to 0? Is that a valid reservation count?

[chrisst]

Adding @rambleraptor as I'm not confident the ansible code will work as is right now since there isn't any ansible update encoder modification.

[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, 119 insertions(+), 5 deletions(-))
Terraform Beta: Diff ( 3 files changed, 119 insertions(+), 5 deletions(-))
Ansible: Diff ( 1 file changed, 18 insertions(+), 5 deletions(-))

[rambleraptor]

I'm not terribly worried about this for now. I'll give you a green check so you can unblock Terraform.

[megan07]

Looking at the downstream this api is following the update with computeOperationWaitTime as though the API returned an operation object. But the API docs don't make it sound like this API supports operations. Also the API has invented it's own error output, which makes me think that they might return an error in a way we won't capture correctly at this time. Can you confirm that bad input (-1 count? stupid large count) returns an actionable error to the user?

I tested with a -1 and it the error returned is clear: Error updating Reservation googleapi: Error 400: Invalid value for field 'specificSkuCount': '-1'. Must be greater than or equal to 1, invalid