chore: update version to 999-SNAPSHOT #6690

Job	Run time
sample_operators_tests (sample-operators/tomcat-operator)	59s
sample_operators_tests (sample-operators/webpage)	52s
sample_operators_tests (sample-operators/metrics-processing)	1m 10s
sample_operators_tests (sample-operators/mysql-schema)	54s
sample_operators_tests (sample-operators/leader-election)	58s
	4m 53s

Provide feedback