Update sphinx requirement from <6.3 to <7.1 (opensearch-project#379)

* Update sphinx requirement from <6.3 to <7.1

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)
- [Commits](sphinx-doc/sphinx@v0.1.61611...v7.0.0)

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

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* Update changelog

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

---------

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

Author: dependabot[bot]

CHANGELOG.md

@@ -22,7 +22,7 @@ Inspired from [Keep a Changelog](https://keepachangelog.com/en/1.0.0/)
 - Fixed CVE-2022-23491 reported in opensearch-dsl-py ([#295](https://github.com/opensearch-project/opensearch-py/pull/295))
 - Update ci workflows ([#318](https://github.com/opensearch-project/opensearch-py/pull/318))
 ### Dependencies
-- Bumps `sphinx` from <1.7 to <6.3
+- Bumps `sphinx` from <1.7 to <7.1
 
 ## [2.2.0]
 ### Added

dev-requirements.txt

@@ -3,7 +3,7 @@ pytest
 pytest-cov
 coverage
 mock
-sphinx<6.3
+sphinx<7.1
 sphinx_rtd_theme
 jinja2