chore: Initial start to migration guide

Author: bryantbiggs

docs/UPGRADE-6.0.md

@@ -0,0 +1,75 @@
+# Upgrade from v5.x to v6.x
+
+If you have any questions regarding this upgrade process, please consult the [`examples`](https://github.com/terraform-aws-modules/terraform-aws-ecs/tree/master/examples) directory:
+If you find a bug, please open an issue with supporting configuration to reproduce.
+
+## List of backwards incompatible changes
+
+- Terraform v1.5.7 is now minimum supported version
+- AWS provider v6.0.0 is now minimum supported version
+
+## Additional changes
+
+### Added
+
+- Support for `region` parameter to specify the AWS region for the resources created if different from the provider region.
+
+### Modified
+
+- Variable definitions now contain detailed `object` types in place of the previously used any type.
+
+### Variable and output changes
+
+1. Removed variables:
+
+    -
+
+2. Renamed variables:
+
+    -
+
+3. Added variables:
+
+    -
+
+4. Removed outputs:
+
+    -
+
+5. Renamed outputs:
+
+    -
+
+6. Added outputs:
+
+    -
+
+## Upgrade Migrations
+
+### Before 5.x Example
+
+```hcl
+module "ecs" {
+  source  = "terraform-aws-modules/ecs/aws"
+  version = "~> 5.0"
+
+  # Truncated for brevity ...
+
+}
+```
+
+### After 6.x Example
+
+```hcl
+module "ecs" {
+  source  = "terraform-aws-modules/ecs/aws"
+  version = "~> 6.0"
+
+  # Truncated for brevity ...
+
+}
+```
+
+### State Changes
+
+TODO