feat!: Drop Rails 6.0 EOL #1969

Job	Run time
kafka / racecar / ubuntu-latest	12m 24s
kafka / rdkafka / ubuntu-latest	10m 21s
kafka / ruby_kafka / ubuntu-latest	4m 34s
mysql / mysql2 / ubuntu-latest	1m 13s
mysql / trilogy / ubuntu-latest	1m 9s
postgresql / pg / ubuntu-latest	3m 8s
postgresql / que / ubuntu-latest	1m 56s
rabbitmq / bunny / ubuntu-latest	1m 4s
redis / redis / ubuntu-latest	2m 2s
redis / resque / ubuntu-latest	1m 46s
other / dalli / ubuntu-latest	2m 56s
redis / sidekiq / ubuntu-latest	4m 53s
other / mongo / ubuntu-latest	2m 50s
	50m 16s

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