chore: add DEV workflow instructions for librarian #2996

Job	Run time
filter	1m 23s
dependencies	3m 37s
sdk-platform-java self-service clients (17)	9m 10s
sdk-platform-java integration (25)	8m 10s
sdk-platform-java units (8)	4m 16s
sdk-platform-java units (11)	4m 35s
unmanaged_dependency_check	14m 59s
sdk-platform-java integration (17)	10m 0s
dependency_analyzer_unit_test	1m 28s
gapic-generator-java (8)	11m 26s
gapic-generator-java-bom	3m 16s
clirr	2m 26s
java8-compatibility	6m 7s
sdk-platform-java integration (11)	10m 19s
sdk-platform-java units (17)	4m 14s
sdk-platform-java integration (21)	10m 33s
sdk-platform-java units (21)	4m 20s
sdk-platform-java units (25)	4m 27s
sdk-platform-java self-service clients (11)	9m 38s
	2h 4m 24s

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