add desc to schema for google_dataproc_cluster

[edwardmedia]

Part of hashicorp/terraform-provider-google#6105

Release Note Template for Downstream PRs (will be copied)

[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.

@rambleraptor, 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 ( 1 file changed, 107 insertions(+), 60 deletions(-))
Terraform Beta: Diff ( 1 file changed, 123 insertions(+), 69 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=121138"

[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, 106 insertions(+), 61 deletions(-))
Terraform Beta: Diff ( 1 file changed, 122 insertions(+), 70 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=121140"