🩹 [Patch]: Add WorkingDirectory input to action configuration and README (#31)

## Description

This pull request introduces a new input parameter to specify the
working directory for the script execution in the PSModule framework.
The changes are reflected in the documentation and the action
configuration file.

### Documentation Update

* `README.md`:
* Added a description for the new `WorkingDirectory` parameter,
specifying its default value as `${{ github.workspace }}`.

### Action Configuration

* `action.yml`:
* Introduced the `WorkingDirectory` input parameter with a description,
default value, and its inclusion in the `runs` section to pass the value
to the script.

## 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

@@ -40,6 +40,7 @@ The Initialize-PSModule action will prepare the runner for the PSModule framewor
 | `Verbose` | Enable verbose output. | `false` | `'false'` |
 | `Version` | Specifies the version of the GitHub module to be installed. The value must be an exact version. | `false` | |
 | `Prerelease` | Allow prerelease versions if available. | `false` | `'false'` |
+| `WorkingDirectory` | The working directory where the script runs. | `false`    | `${{ github.workspace }}` |
 
 ## Example
 

action.yml

@@ -21,6 +21,10 @@ inputs:
     description: Allow prerelease versions if available.
     required: false
     default: 'false'
+  WorkingDirectory:
+    description: The working directory where the script will run from.
+    required: false
+    default: ${{ github.workspace }}
 
 runs:
   using: composite
@@ -32,6 +36,7 @@ runs:
         Prerelease: ${{ inputs.Prerelease }}
         Verbose: ${{ inputs.Verbose }}
         Version: ${{ inputs.Version }}
+        WorkingDirectory: ${{ inputs.WorkingDirectory }}
         Script: |
           # Initialize-PSModule
           ${{ github.action_path }}\scripts\main.ps1