📖 [Docs]: Add section for similar projects in README.md (#5)

## Description

This pull request adds an "Alternatives" section that lists similar
GitHub actions.

## Type of change

<!-- Use the check-boxes [x] on the options that are relevant. -->

- [x] 📖 [Docs]
- [ ] 🪲 [Fix]
- [ ] 🩹 [Patch]
- [ ] ⚠️ [Security fix]
- [ ] 🚀 [Feature]
- [ ] 🌟 [Breaking change]

## Checklist

<!-- Use the check-boxes [x] on the options that are relevant. -->

- [x] I have performed a self-review of my own code
- [x] I have commented my code, particularly in hard-to-understand areas

Author: MariusStorhaug

README.md

@@ -92,3 +92,10 @@ jobs:
           Write-Output $data
 
 ```
+
+## Alternatives
+
+[github/issue-parser](https://github.com/github/issue-parser)
+[issue-ops/parser](https://github.com/issue-ops/parser)
+[peter-murray/issue-forms-body-parser](https://github.com/peter-murray/issue-forms-body-parser)
+[peter-murray/issue-body-parser-action](https://github.com/peter-murray/issue-body-parser-action)