Bump bitnami/mysqld-exporter

Bumps bitnami/mysqld-exporter from 0.14.0-debian-11-r27 to 0.15.0-debian-11-r27.

---
updated-dependencies:
- dependency-name: bitnami/mysqld-exporter
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

Author: dependabot[bot]

values.yaml

@@ -148,7 +148,7 @@ metrics:
   image:
     registry: docker.io
     repository: bitnami/mysqld-exporter
-    tag: 0.14.0-debian-11-r27
+    tag: 0.15.0-debian-11-r27
     pullPolicy: IfNotPresent
   resources: {}
   annotations: