Update elasticsearch requirement from <8,>=7 to >=7,<9

Updates the requirements on [elasticsearch](https://github.com/elastic/elasticsearch-py) to permit the latest version.
- [Release notes](https://github.com/elastic/elasticsearch-py/releases)
- [Commits](elastic/elasticsearch-py@7.0.0...v8.12.1)

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

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

base-requirements.txt

@@ -22,7 +22,7 @@ chardet==4.0.0
 # TODO: We may drop 'django-imagekit' completely.
 django-imagekit==4.0.2
 django-haystack==3.2.1
-elasticsearch>=7,<8
+elasticsearch>=7,<9
 # TODO: 0.14.0 only supports Django 1.8 and 1.11.
 django-tastypie==0.14.3