[DEV] Update sphinx requirement from ~=7.0 to >=7,<9 (#1029)

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](https://github.com/sphinx-doc/sphinx/compare/v7.0.0...v8.0.0)

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

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

pyproject.toml

@@ -52,7 +52,7 @@ lint = [
     "pylint==3.2.7",
 ]
 docs = [
-    "sphinx~=7.0",
+    "sphinx>=7,<9",
     "sphinx-rtd-theme~=2.0",
     "sphinx-book-theme~=1.0",
 ]