Skip CI on PR synchronize as tests will already run on PR opening #920

Job	Run time
build-dse (jdk8, LifecycleIT)	13m 36s
build-dse (jdk8, KeepAliveIT)	11m 40s
build-dse (jdk8, NonDestructiveOpsIT)	16m 1s
build-dse (jdk8, DestructiveOpsIT)	11m 32s
build-dse (jdk8, DSESpecificIT)	9m 16s
build-dse (ubi, LifecycleIT)	10m 17s
build-dse (ubi, KeepAliveIT)	9m 1s
build-dse (ubi, NonDestructiveOpsIT)	16m 22s
build-dse (ubi, DestructiveOpsIT)	6m 48s
build-dse (ubi, DSESpecificIT)	5m 34s
build-dse7	4m 13s
build-oss (3.11, LifecycleIT)	5m 38s
build-oss (3.11, KeepAliveIT)	5m 49s
build-oss (3.11, NonDestructiveOpsIT)	13m 40s
build-oss (3.11, DestructiveOpsIT)	6m 14s
build-oss (4.0, LifecycleIT)	9m 59s
build-oss (4.0, KeepAliveIT)	6m 59s
build-oss (4.0, NonDestructiveOpsIT)	13m 47s
build-oss (4.0, DestructiveOpsIT)	5m 58s
build-oss (4.1, LifecycleIT)	11m 5s
build-oss (4.1, KeepAliveIT)	6m 41s
build-oss (4.1, NonDestructiveOpsIT)	14m 4s
build-oss (4.1, DestructiveOpsIT)	5m 49s
build-oss (3.11_ubi, LifecycleIT)	8m 10s
build-oss (3.11_ubi, KeepAliveIT)	7m 43s
build-oss (3.11_ubi, NonDestructiveOpsIT)	12m 0s
build-oss (3.11_ubi, DestructiveOpsIT)	4m 57s
build-oss (4.0_ubi, LifecycleIT)	10m 46s
build-oss (4.0_ubi, KeepAliveIT)	8m 19s
build-oss (4.0_ubi, NonDestructiveOpsIT)	12m 54s
build-oss (4.0_ubi, DestructiveOpsIT)	7m 43s
build-oss (4.1_ubi, LifecycleIT)	9m 8s
build-oss (4.1_ubi, KeepAliveIT)	9m 32s
build-oss (4.1_ubi, NonDestructiveOpsIT)	14m 37s
build-oss (4.1_ubi, DestructiveOpsIT)	7m 28s
Publish DSE 6.8 Ubuntu image	0s
Publish DSE 6.8 UBI 8 image	0s
Publish ${{ matrix.cassandra-version }} Cassandra image	0s
	5h 33m 20s

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