Allow 'map_public_ip_on_launch' to be changed on default subnet

[ewbankkit]

Fixes #4291.

Acceptance tests:

make testacc TEST=./aws/ TESTARGS='-run=TestAccAWSDefaultSubnet_'
==> Checking that code complies with gofmt requirements...
TF_ACC=1 go test ./aws/ -v -run=TestAccAWSDefaultSubnet_ -timeout 120m
=== RUN   TestAccAWSDefaultSubnet_basic
--- PASS: TestAccAWSDefaultSubnet_basic (13.21s)
=== RUN   TestAccAWSDefaultSubnet_publicIp
--- PASS: TestAccAWSDefaultSubnet_publicIp (23.26s)
PASS
ok  	github.com/terraform-providers/terraform-provider-aws/aws	36.494s

[ewbankkit]

For backwards compatibility I don't set the Default: false flag here as is done for the equivalent attribute in the aws_subnet resource.

[ewbankkit]

In the related issue I mention the same problem with the ipv6_cidr_block and assign_ipv6_address_on_creation attribute but I have not addressed them here as fixing that is more involved. I'll open a new issue for that.

[bflad]

Thanks for this @ewbankkit! 🚀

2 tests passed (all tests)
=== RUN   TestAccAWSDefaultSubnet_basic
--- PASS: TestAccAWSDefaultSubnet_basic (6.16s)
=== RUN   TestAccAWSDefaultSubnet_publicIp
--- PASS: TestAccAWSDefaultSubnet_publicIp (10.69s)

[bflad]

This has been released in version 1.17.0 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!