chore: add flatmap example (#68) #10

Job	Run time
Build, Tag, and Push Image (examples/map-cat)	2m 1s
Build, Tag, and Push Image (examples/map-cat)	2m 1s
Build, Tag, and Push Image (examples/map-tickgen-serde)	2m 12s
Build, Tag, and Push Image (examples/map-tickgen-serde)	1m 59s
Build, Tag, and Push Image (examples/mapt-event-time-filter)	2m 2s
Build, Tag, and Push Image (examples/mapt-event-time-filter)	2m 2s
Build, Tag, and Push Image (examples/reduce-counter)	2m 14s
Build, Tag, and Push Image (examples/reduce-counter)	2m 21s
Build, Tag, and Push Image (examples/sideinput)	2m 10s
Build, Tag, and Push Image (examples/sideinput)	3m 2s
Build, Tag, and Push Image (examples/sideinput/udf)	2m 22s
Build, Tag, and Push Image (examples/sideinput/udf)	2m 35s
Build, Tag, and Push Image (examples/simple-source)	2m 2s
Build, Tag, and Push Image (examples/simple-source)	2m 2s
Build, Tag, and Push Image (examples/sink-log)	2m 13s
Build, Tag, and Push Image (examples/sink-log)	2m 33s
Build, Tag, and Push Image (examples/source-transformer-now)	2m 24s
Build, Tag, and Push Image (examples/source-transformer-now)	2m 44s
Build, Tag, and Push Image (examples/batchmap-flatmap)	2m 6s
Build, Tag, and Push Image (examples/batchmap-flatmap)	2m 6s
Build, Tag, and Push Image (examples/batchmap-cat)	2m 4s
Build, Tag, and Push Image (examples/batchmap-cat)	2m 1s
	49m 16s

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