build: update monorepo-migration scripts #16953

Job	Run time
root-pom	1m 44s
owlbot-yaml	1m 4s
gitignore_correctness	59s
gapic-bom	1m 46s
owlbot-py	1m 6s
package_name_check	1m 5s
generate-readme	1m 10s
group_id_check_for_maps_libraries	7m 19s
	16m 13s

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