Add semantic versioning guidelines and NOTES.md documentation info

Co-authored-by: markphip <933108+markphip@users.noreply.github.com>

Author: Copilot

.copilot-instructions.md

@@ -13,8 +13,8 @@ This repository contains [devcontainer features](https://containers.dev/implemen
 Each feature in `/src/{feature-name}/` contains:
 - `devcontainer-feature.json` - Feature metadata, options, and configuration
 - `install.sh` - Installation script (main implementation)
-- `README.md` - Feature documentation
-- Optional: `NOTES.md` for implementation notes
+- `README.md` - Feature documentation (auto-generated, do not edit manually)
+- Optional: `NOTES.md` - Implementation notes that get included in README.md generation (auto-generated, do not edit manually)
 
 ### Testing Structure
 - `/test/{feature-name}/` - Feature-specific tests with `scenarios.json` and test scripts
@@ -34,6 +34,17 @@ Each feature in `/src/{feature-name}/` contains:
 
 ## Development Guidelines
 
+### Semantic Versioning
+Features use [semantic versioning (SemVer)](https://semver.org/):
+- **MAJOR** version for incompatible API changes
+- **MINOR** version for backward-compatible functionality additions
+- **PATCH** version for backward-compatible bug fixes
+
+When making changes to a feature:
+1. Update the `version` field in `devcontainer-feature.json`
+2. Follow SemVer guidelines based on the type of change
+3. Document breaking changes in the feature description or NOTES.md
+
 ### Creating a New Feature
 1. Create directory structure: `/src/{feature-name}/`
 2. Write `devcontainer-feature.json` with proper metadata:
@@ -169,9 +180,10 @@ fi
 ### Pull Request Process
 1. Create feature branch from `main`
 2. Implement feature with comprehensive tests
-3. Ensure all CI checks pass
-4. Update documentation as needed
-5. Request review from maintainers
+3. Update the `version` field in `devcontainer-feature.json` following semantic versioning
+4. Ensure all CI checks pass
+5. Update documentation as needed
+6. Request review from maintainers
 
 ### Code Review Checklist
 - [ ] Feature follows repository conventions