Bump elasticsearch from 7.7.0 to 7.8.0 (#14108)

Bumps [elasticsearch](https://github.com/elastic/elasticsearch-ruby) from 7.7.0 to 7.8.0.
- [Release notes](https://github.com/elastic/elasticsearch-ruby/releases)
- [Changelog](https://github.com/elastic/elasticsearch-ruby/blob/master/CHANGELOG.md)
- [Commits](https://github.com/elastic/elasticsearch-ruby/compare/7.7.0...v7.8.0)

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

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

Gemfile.lock

@@ -202,13 +202,13 @@ GEM
       railties (>= 3.2, < 6.1)
     e2mmap (0.1.0)
     ed25519 (1.2.4)
-    elasticsearch (7.7.0)
-      elasticsearch-api (= 7.7.0)
-      elasticsearch-transport (= 7.7.0)
-    elasticsearch-api (7.7.0)
+    elasticsearch (7.8.0)
+      elasticsearch-api (= 7.8.0)
+      elasticsearch-transport (= 7.8.0)
+    elasticsearch-api (7.8.0)
       multi_json
     elasticsearch-dsl (0.1.9)
-    elasticsearch-transport (7.7.0)
+    elasticsearch-transport (7.8.0)
       faraday (~> 1)
       multi_json
     encryptor (3.0.0)