[GCP] [CloudSQL] Add dashboards (#7368)

* add sql server dashboard

* add mysql dashboard

* add postgresql dashboard

* bump package version

* fix mysql version input control group label

Author: gpop63

packages/gcp/changelog.yml

@@ -1,4 +1,9 @@
 # newer versions go on top
+- version: "2.27.0"
+  changes:
+    - description: Add GCP CloudSQL MySQL, SQL Server and PostgreSQL dashboards.
+      type: enhancement
+      link: https://github.com/elastic/integrations/pull/7368
 - version: "2.26.0"
   changes:
     - description: Fix GCP loadbalancing_metrics fields prefix.