Fixes GHSA-r3hx-x5rh-p9vv: via eval() in Elasticsearch Result Deserialization

https://github.com/django-haystack/django-haystack/security/advisories/GHSA-r3hx-x5rh-p9vv

What's Changed

https://github.com/django-haystack/django-haystack/releases/tag/v3.4.0

• Remove obsolete ElasticSearch2 support and tests by @claudep in https://github.com/django-haystack/django-haystack/pull/1978
• Add Django v5.1 to the testing by @cclauss in https://github.com/django-haystack/django-haystack/pull/1991
• GitHub Actions: Add Python 3.13 to the testing by @cclauss in https://github.com/django-haystack/django-haystack/pull/1997
• Fix typo. by @andresmrm in https://github.com/django-haystack/django-haystack/pull/1998
• Fix RelatedSearchQueryset.load_all() truncating results by @craigds in https://github.com/django-haystack/django-haystack/pull/2012
• [FIXED] -- handle trailing slash in Solr index URL for core reload. by @DhavalGojiya in https://github.com/django-haystack/django-haystack/pull/1968
• Bump the github-actions group with 2 updates by @dependabot[bot] in https://github.com/django-haystack/django-haystack/pull/2018
• Update license field to use proper SPDX identifier by @leifdreizler in https://github.com/django-haystack/django-haystack/pull/2016
• dev: Update Python dependencies by @kingbuzzman in https://github.com/django-haystack/django-haystack/pull/2019
• dev: Update django by @kingbuzzman in https://github.com/django-haystack/django-haystack/pull/2020
• fix: handle HEAD requests like GET in generic_views by @janheini in https://github.com/django-haystack/django-haystack/pull/2015
• feat: Add requires-python to pyproject.toml (PEP 621) by @DhavalGojiya in https://github.com/django-haystack/django-haystack/pull/2039
• Add Python 3.14 and 3.14t to the testing by @cclauss in https://github.com/django-haystack/django-haystack/pull/2031
• Fix race condition in ConnectionRouter.routers lazy initialization by @craigds in https://github.com/django-haystack/django-haystack/pull/2048
• add postgres backend to backend_support.rst by @fgregg in https://github.com/django-haystack/django-haystack/pull/2044
• Actions: limit permissions for tests by @acdha in https://github.com/django-haystack/django-haystack/pull/2053
• GitHub Actions: zizmor fixes by @acdha in https://github.com/django-haystack/django-haystack/pull/2055