Update jsch to 0.2.18 #285

Job	Run time
initiate-java-modules	32s
test (kafka-connect-azure-eventhubs)	45s
test (kafka-connect-azure-servicebus)	48s
test (kafka-connect-common)	47s
test (kafka-connect-gcp-common)	55s
test (kafka-connect-gcp-pubsub)	57s
test (kafka-connect-query-language)	49s
build-and-cache (kafka-connect-azure-eventhubs)	43s
build-and-cache (kafka-connect-azure-servicebus)	52s
build-and-cache (kafka-connect-gcp-common)	50s
build-and-cache (kafka-connect-gcp-pubsub)	1m 10s
jar-dependency-check (kafka-connect-azure-eventhubs)	26s
jar-dependency-check (kafka-connect-azure-servicebus)	26s
jar-dependency-check (kafka-connect-gcp-common)	31s
jar-dependency-check (kafka-connect-gcp-pubsub)	27s
(Java) Final Stage	1s
	10m 59s

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