docs: adds the missing osl license file

[asadali214]

What

This PR adds an OSL license file, the same as the one this library is forked from

Why

The composer.json has already specified the LICENSE as OSL 3.0. but the license file was missing from the source code.

Closes #63

Type of change

Select multiple if applicable.

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause a breaking change)
• Tests (adds or updates tests)
• Documentation (adds or updates documentation)
• Refactor (style improvements, performance improvements, code refactoring)
• Revert (reverts a commit)
• CI/Build (adds or updates a script, change in external dependencies)

Dependency Change

N/A

Breaking change

N/A

Testing

N/A

Checklist

• My code follows the coding conventions
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have added new unit tests

[Copilot]

Pull Request Overview

This PR adds the missing Open Software License v3.0 (OSL-3.0) file to align with the license specification in composer.json and resolve issue #63.

• Adds the complete OSL-3.0 license text to a new LICENSE file
• Updates the README.rst to link the license badge to the local LICENSE file instead of the external Packagist page

Reviewed Changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated no comments.

File	Description
LICENSE	Adds the complete OSL-3.0 license text as a new file
README.rst	Updates license badge link to point to local LICENSE file

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[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud