🩹 [Patch]: Add a diagram showing how Process-PSModule works (#32)

## Description

- Add a diagram showing how Process-PSModule works

## Type of change

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

- [ ] 📖 [Docs]
- [ ] 🪲 [Fix]
- [x] 🩹 [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

@@ -18,6 +18,8 @@ The workflow is designed to be trigger on pull requests to the repository's defa
 When a pull request is opened, closed, reopened, synchronized (push), or labeled, the workflow will run.
 Depending on the labels in the pull requests, the workflow will result in different outcomes.
 
+![Process diagram](./assets/Process-PSModule.png)
+
 - [Test-PSModule](https://github.com/PSModule/Test-PSModule/) - Tests the source code using PSScriptAnalyzer, PSModule source code tests suites. This runs on 4 different environments to check compatibility.
   - PowerShell 7.x on Windows, Ubuntu and macOS.
   - Windows PowerShell 5.1 on Windows.