chore: Filter out non-semver versions in update_generation_config.sh #15642

Job	Run time
generate-readme	57s
group_id_check_for_maps_libraries	6m 46s
gapic-bom	1m 32s
owlbot-yaml	50s
root-pom	1m 29s
package_name_check	50s
gitignore_correctness	49s
owlbot-py	58s
	14m 11s

Provide feedback