Update docker.io/prom/mysqld-exporter Docker tag to v0.16.0

Automtated minor upgrade of MySQL exporter Docker container by means of Watchtower with dependency update facilitated by Mend's Renovate Bot.

This MR contains the following updates:

Package	Update	Change
docker.io/prom/mysqld-exporter	minor	`v0.15.1` -> `v0.16.0`

prometheus/mysqld_exporter (docker.io/prom/mysqld-exporter)

Changes:

[CHANGE] Replace logging library go-kit/log with slog #875
[FEATURE] Support for prometheus scrape timeout in probe endpoint #828
[ENHANCEMENT] Support MySQL 8.4 replicas syntax #837
[ENHANCEMENT] Fetch lock time and cpu time from performance schema #862
[ENHANCEMENT] Add the instance struct to handle connections #859
[ENHANCEMENT] Optimize code by using built-in constants in the standard lib #844
[BUGFIX] Fix fetching tmpTables vs tmpDiskTables from performance_schema #853
[BUGFIX] Skip SPACE_TYPE column for MariaDB >=10.5 #860
[BUGFIX] Fixed parsing of timestamps with non-zero padded days #841
[BUGFIX] Fix auto_increment metric collection errors caused by using collation in INFORMATION_SCHEMA searches #833
[BUGFIX] Fix race condition in ReloadConfig #760
[BUGFIX] Change processlist query to support ONLY_FULL_GROUP_BY sql_mode #684
[BUGFIX] replication_applier_status_by_worker requires mysql 8.0 #683
[BUGFIX] Update docker registry link in README.md #813
[BUGFIX] Fix Docker run command and update documentation for cnf file handling #843
[BUGFIX] info_schema_tables: do not collect the sys schema #879