ADR for Multi-Region Update

Why these changes are being introduced:
Once again, the CDPS project is pushing us to update one of our core
infrastructure repositories to handle deployment of resources to
multiple regions.

How this addresses that need:
* Create and ADR for this decision
* Minor formatting change to the PR template

Side effects of this change:
None.

Relevant ticket(s):
* https://mitlibraries.atlassian.net/browse/IR-238

Author: cabutlermit

.github/PULL_REQUEST_TEMPLATE.md

@@ -1,30 +1,30 @@
-#### Developer Checklist
+## Developer Checklist
 
 - [ ] The README contains any additional info needed outside of the terraform docs generated
 - [ ] Any special variables have values configured in AWS SSM
 - [ ] Stakeholder approval has been confirmed (or is not needed)
 
-#### What does this PR do?
+## What does this PR do?
 
 A few sentences describing the overall goals of the pull request's commits.
 Why are we making these changes? Is there more work to be done to fully
 achieve these goals?
 
-#### Helpful background context
+## Helpful background context
 
 Describe any additional context beyond what the PR accomplishes if it is likely
 to be useful to a reviewer.
 
 Delete this section if it isn't applicable to the PR.
 
-#### What are the relevant tickets?
+## What are the relevant tickets?
 
 Include links to Jira Software and/or Jira Service Management tickets here.
 
-#### Requires Database Migrations?
+## Requires Database Migrations?
 
 YES | NO
 
-#### Includes new or updated dependencies?
+## Includes new or updated dependencies?
 
 YES | NO

docs/adrs/0004-make-repo-multi-region.md

@@ -0,0 +1,23 @@
+# 4. Make repository mulit-region capable
+
+Date: 2025-05-06
+
+## Status
+
+Proposed
+
+## Context
+
+We are now at the place in our infrastructure that we need to be able to deploy ECR repositories in  multiple AWS regions so that we can deploy containerized applications (Fargate & Lambda) in mulitple regions. This is primarly driven by the CDPS project, but will be available to any other project that expects containers in more than just `us-east-1`.
+
+As we extend this to multiple regions, it is **very import** that we do not modify any of the existing outputs from this repository, either to SSM Parameter Store or to Terraform Cloud outputs -- too many other repositories are already dependent on those values and would all need refactoring if any of the outputs change.
+
+## Decision
+
+1. Add additional provider blocks in the root of the repository, as needed.
+1. Update the embedded `ecr` module to handle ECR repository creation for containers that need to be deployed in multiple AWS regions.
+1. Update the generated GHA workflows and Makefile outputs to support multiple AWS regions.
+
+## Consequences
+
+If this is done correctly, there will be no consequences.