Remove gitter reference, add Google Form for Slack

Author: justinretzolk

README.md

@@ -21,7 +21,6 @@ The [AWS Provider](https://registry.terraform.io/providers/hashicorp/aws/latest/
 - [FAQ](https://hashicorp.github.io/terraform-provider-aws/faq/)
 - [Tutorials](https://learn.hashicorp.com/collections/terraform/aws-get-started)
 - [discuss.hashicorp.com](https://discuss.hashicorp.com/c/terraform-providers/tf-aws/)
-- [gitter](https://gitter.im/hashicorp-terraform/Lobby)
 - [Google Groups](http://groups.google.com/group/terraform-tool)
 
 _**Please note:** We take Terraform's security and our users' trust very seriously. If you believe you have found a security issue in the Terraform AWS Provider, please responsibly disclose it by contacting us at [email protected]._

docs/index.md

@@ -45,3 +45,7 @@ Pull requests are usually triaged within a few days of creation and are prioriti
 ### Submit an Issue
 
 In addition to contributions, we welcome [bug reports](https://github.com/hashicorp/terraform-provider-aws/issues/new?assignees=&labels=&template=Bug_Report.md) and [feature requests](https://github.com/hashicorp/terraform-provider-aws/issues/new?assignees=&labels=enhancement&template=Feature_Request.md).
+
+### Join the Contributors Slack
+
+For frequent contributors, it's useful to join the contributors Slack channel hosted within the HashiCorp Slack workspace. To do so, fill out the [request form](https://forms.gle/Gf9ZAmUYXuzafkct6) to request to be added. Please allow time for the request to be reviewed and processed.