Add CI job for 8.8 branch (#1857)

* Add CI automation for 8.8 branch

* Drop tests for old minor versions

Author: JoshMock

.ci/jobs/elastic+elasticsearch-js+8.2.yml

@@ -1,13 +1,13 @@
 ---
 - job:
-    name: elastic+elasticsearch-js+8.1
-    display-name: 'elastic / elasticsearch-js # 8.1'
-    description: Testing the elasticsearch-js 8.1 branch.
+    name: elastic+elasticsearch-js+8.8
+    display-name: 'elastic / elasticsearch-js # 8.8'
+    description: Testing the elasticsearch-js 8.8 branch.
     junit_results: "*-junit.xml"
     parameters:
     - string:
         name: branch_specifier
-        default: refs/heads/8.1
+        default: refs/heads/8.8
         description: the Git branch specifier to build (<branchName>, <tagName>,
           <commitId>, etc.)
     triggers: