default tags: add changelog and upgrade guide entry (#31343)

* add CHANGELOG entry

* add default tags to upgrade guide

* fix typo

Author: johnsonaj

.changelog/30793.txt

@@ -0,0 +1,11 @@
+```release-note:enhancement
+provider: Duplicate `default_tags` can now be included and will be overwritten by resource `tags`
+```
+
+```release-note:enhancement
+provider: Allow `default_tags` and resource `tags` to include zero values `""`
+```
+
+```release-note:enhancement
+provider: Allow `computed` `tags` on resources
+```

website/docs/guides/version-5-upgrade.html.md

@@ -18,6 +18,7 @@ Upgrade topics:
 
 - [Provider Version Configuration](#provider-version-configuration)
 - [Provider Arguments](#provider-arguments)
+- [Default Tags](#default-tags)
 - [Data Source: aws_api_gateway_rest_api](#data-source-aws_api_gateway_rest_api)
 - [Data Source: aws_identitystore_group](#data-source-aws_identitystore_group)
 - [Data Source: aws_identitystore_user](#data-source-aws_identitystore_user)
@@ -167,6 +168,14 @@ The [`aws_redshift_service_account`](/docs/providers/aws/d/redshift_service_acco
 
 The `aws_subnet_ids` data source has been removed. Use the [`aws_subnets`](/docs/providers/aws/d/subnets.html) data source instead.
 
+## Default Tags
+
+The following enhancements are included:
+
+* Duplicate `default_tags` can now be included and will be overwritten by resource `tags`.
+* Zero value tags, `""`, can now be included in both `default_tags` and resource `tags`.
+* Tags can now be `computed`.
+
 ## EC2-Classic Retirement
 
 Following the retirement of EC2-Classic a number of resources and attributes have been removed.