Update sphinx requirement from ~=7.4.7 to ~=8.1.3

Updates the requirements on [sphinx](https://github.com/sphinx-doc/sphinx) to permit the latest version.
- [Release notes](https://github.com/sphinx-doc/sphinx/releases)
- [Changelog](https://github.com/sphinx-doc/sphinx/blob/master/CHANGES.rst)
- [Commits](sphinx-doc/sphinx@v7.4.7...v8.1.3)

---
updated-dependencies:
- dependency-name: sphinx
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

pyproject.toml

@@ -37,7 +37,7 @@ Discord = "https://discord.gg/TPBU2sa8Et"
 visualization = ["matplotlib"]
 test = ["pytest", "pytest-cov"]
 lint = ["isort", "ruff", "qbraid-cli"]
-docs = ["sphinx~=7.4.7", "sphinx-autodoc-typehints>=1.24,<2.5", "sphinx-rtd-theme~=3.0.1", "docutils<0.22", "sphinx-copybutton"]
+docs = ["sphinx~=8.1.3", "sphinx-autodoc-typehints>=1.24,<2.5", "sphinx-rtd-theme~=3.0.1", "docutils<0.22", "sphinx-copybutton"]
 
 [tool.setuptools_scm]
 write_to = "qbraid_algorithms/_version.py"