Updated ReadTheDocs bade to new url (#339)

* Updated ReadTheDocs bade to new url

* Auto update version

* Auto update version

Co-authored-by: Dev version update bot <chae-yeun@xanadu.ai>
Co-authored-by: Josh Izaac <josh146@gmail.com>
Co-authored-by: Dev version update bot <github-actions[bot]@users.noreply.github.com>

README.rst

@@ -13,7 +13,7 @@ PennyLane-Lightning Plugin
     :alt: CodeFactor Grade
     :target: https://www.codefactor.io/repository/github/pennylaneai/pennylane-lightning
 
-.. image:: https://img.shields.io/readthedocs/pennylane-lightning.svg?logo=read-the-docs&style=flat-square
+.. image:: https://readthedocs.com/projects/xanaduai-pennylane-lightning/badge/?version=latest&style=flat-square
     :alt: Read the Docs
     :target: https://docs.pennylane.ai/projects/lightning
 

pennylane_lightning/_version.py

@@ -16,4 +16,4 @@
    Version number (major.minor.patch[-label])
 """
 
-__version__ = "0.26.0-dev8"
+__version__ = "0.26.0-dev9"