r/aws_kms_grant: Add Support for Referencing CMK by ARN

[brandonstevens]

Fixes #4141

Changes proposed in this pull request:

• Add Support for Referencing CMK by ARN which includes CMKs in a different AWS accounts

Output from acceptance testing:

$ make testacc TESTARGS='-run=TestAWSKmsGrant_*'
==> Checking that code complies with gofmt requirements...
TF_ACC=1 go test ./... -v -run=TestAWSKmsGrant_* -timeout 120m
?   	github.com/terraform-providers/terraform-provider-aws	[no test files]
=== RUN   TestAWSKmsGrant_Basic
--- PASS: TestAWSKmsGrant_Basic (102.16s)
=== RUN   TestAWSKmsGrant_withConstraints
--- PASS: TestAWSKmsGrant_withConstraints (143.80s)
=== RUN   TestAWSKmsGrant_withRetiringPrincipal
--- PASS: TestAWSKmsGrant_withRetiringPrincipal (89.55s)
=== RUN   TestAWSKmsGrant_bare
--- PASS: TestAWSKmsGrant_bare (94.40s)
=== RUN   TestAWSKmsGrant_ARN
--- PASS: TestAWSKmsGrant_ARN (90.32s)
PASS
ok  	github.com/terraform-providers/terraform-provider-aws/aws	520.244s

[bflad]

Thanks for this great contribution, @brandonstevens! LGTM with minor nitpick for GovCloud support, which I'll adjust on merge. 🚀

5 tests passed (all tests)
=== RUN   TestAWSKmsGrant_bare
--- PASS: TestAWSKmsGrant_bare (43.02s)
=== RUN   TestAWSKmsGrant_ARN
--- PASS: TestAWSKmsGrant_ARN (43.10s)
=== RUN   TestAWSKmsGrant_withRetiringPrincipal
--- PASS: TestAWSKmsGrant_withRetiringPrincipal (43.62s)
=== RUN   TestAWSKmsGrant_Basic
--- PASS: TestAWSKmsGrant_Basic (44.66s)
=== RUN   TestAWSKmsGrant_withConstraints
--- PASS: TestAWSKmsGrant_withConstraints (65.28s)

[bflad]

Minor nitpick: to support GovCloud (US) partition ARNs (arn:aws-us-gov:kms:) with this change, we can just check for the arn: prefix 👍 I'll adjust this on merge as KMS key IDs should never start with that string.

[bflad]

This has been released in version 1.24.0 of the AWS provider. Please see the Terraform documentation on provider versioning or reach out if you need any assistance upgrading.

[ghost]

I'm going to lock this issue because it has been closed for 30 days ⏳. This helps our maintainers find and focus on the active issues.

If you feel this issue should be reopened, we encourage creating a new issue linking back to this one for added context. Thanks!