Update README.md to add the License section (#209)

Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>

README.md

@@ -11,7 +11,6 @@
 [![Imports: isort](https://img.shields.io/badge/%20imports-isort-%231674b1?style=for-the-badge&labelColor=ef8336)](https://pycqa.github.io/isort/)
 [![Ruff](https://img.shields.io/endpoint?url=https://raw.githubusercontent.com/astral-sh/ruff/main/assets/badge/v2.json&style=for-the-badge)](https://github.com/astral-sh/ruff)
 [![code style: prettier](https://img.shields.io/badge/code_style-prettier-ff69b4.svg?style=for-the-badge)](https://github.com/prettier/prettier)
-[![License: GPL v3](https://img.shields.io/badge/License-GPLv3-blue.svg?style=for-the-badge)](https://www.gnu.org/licenses/gpl-3.0)
 
 Contributions are _very welcome_ but first see [Contributing](#contributions).
 This project is released with a [Contributor Code of Conduct](CODE_OF_CONDUCT.md).
@@ -33,6 +32,7 @@ Enjoying scikit-gmsh? Show your support with a [GitHub star](https://github.com/
 - [Installation](#installation)
   - [Developer](#developer)
 - [Usage](#usage)
+- [License](#license)
 
 <!-- END doctoc generated TOC please keep comment here to allow auto update -->
 
@@ -130,3 +130,9 @@ clipped = mesh.clip(origin=(0.0, 0.0, 0.0), normal=(0.0, 0.0, 1.0), crinkle=True
 <p align="center">
 <img src="https://raw.githubusercontent.com/pyvista/scikit-gmsh/main/docs/_static/delaunay_3d_02.png" align="center" width=512 >
 </p>
+
+## License
+
+[![License: GPL v3](https://img.shields.io/badge/License-GPLv3-blue.svg?style=for-the-badge)](https://www.gnu.org/licenses/gpl-3.0)
+
+This software is published under the [GPLv3 license](https://www.gnu.org/licenses/gpl-3.0.en.html).