PMM-8874 Merged tickets for release

Merged:
- PMM-8849 Fixed panic on nil data
- PMM-8539_cluster_role_label
- PMM-8539 Fixed cluster role cluster
- PMM-7424 Add dbStatsCollector
- PMM-7116 Incorrect STARTUP state

Updated mongo driver and ci-lint

Author: percona-csalguero

CHANGELOG

@@ -1,6 +1,12 @@
 Release 0.20.8
-Improvement PMM-7424: Add dbStats metric
-Improvement         : Add support for compatible mode for dbStats metric to provide old metrics
+
+Fixed bug   PMM-8849: Fixed panic on nil data
+Improvement PMM-8772: DBStats are disabled by default. Adde 'enable' parameter
+Fixed bug   PMM-8539: cl_role is always "shardsvr" even for configsvr
+Fixed bug   PMM-8489: Fixed topology labels on mongos
+Improvement PMM-7424: Add support for compatible mode for dbStats metric to provide old metrics
+Improvemebt PMM-7116: myState metric always has a value
+Improvement PR  #344: Documented minimum permissions needed to collect data
 
 Release 0.20.7 released 2021-08-10