[CI] Add 7.11, remove 7.9

Author: swallez

.ci/jobs/elastic+elasticsearch-rs+7.9.yml renamed to .ci/jobs/elastic+elasticsearch-rs+7.11.yml

@@ -1,13 +1,13 @@
 ---
 - job:
-    name: elastic+elasticsearch-rs+7.9
-    display-name: 'elastic / elasticsearch-rs # 7.9'
-    description: Testing the elasticsearch-rs 7.9 branch.
+    name: elastic+elasticsearch-rs+7.11
+    display-name: 'elastic / elasticsearch-rs # 7.11'
+    description: Testing the elasticsearch-rs 7.11 branch.
     junit_results: "*-junit.xml"
     parameters:
       - string:
           name: branch_specifier
-          default: refs/heads/7.9
+          default: refs/heads/7.11
           description: The Git branch specifier to build
     triggers:
       - github