fix: make google_compute_network mtu field updatable

[bharathkkb]

fixes hashicorp/terraform-provider-google#8091

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)

compute: made mtu field in `google_compute_network` updatable

[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.

@melinath, 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 Beta: Diff ( 1 file changed, 1 insertion(+), 1 deletion(-))
Ansible: Diff ( 1 file changed, 1 insertion(+), 1 deletion(-))

[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=164767"

[modular-magician]

I have triggered VCR tests in RECORDING mode for the following tests that failed during VCR: TestAccDataSourceStorageBucketObjectContent_Basic|TestAccActiveDirectoryDomainTrust_activeDirectoryDomainTrustBasicExample|TestAccContainerCluster_withConfidentialNodes|TestAccContainerCluster_withPrivateClusterConfigMissingCidrBlock|TestAccContainerCluster_withIPv4Error|TestAccContainerNodePool_withKubeletConfig|TestAccDataprocJob_Spark You can view the result here: "https://ci-oss.hashicorp.engineering/viewQueued.html?itemId=164778"

[melinath]

It looks like the Network resource is marked as input: true as a whole, which means that it is irrelevant what the individual properties say. I think you will need to remove that line as well. It looks like the resource can be patched, so that line (marking the entire resource as input-only) is probably a mistake.

[melinath]

@bharathkkb just wanted to check in whether you're still working on this PR?

[melinath]

I'm closing this issue since it's been inactive for a long time now. Please open a new PR if you're still interested in working on this issue.