chore(launcher): fix deprecated '--logger=capnslog' flag warning #669

Job	Run time
checks / deps	5s
checks / deps	5s
checks / check	1m 27s
checks / check	1m 27s
build (11, gcr.io/etcd-development/etcd:v3.5.9) / build	8m 55s
build (11, gcr.io/etcd-development/etcd:v3.5.9) / build	8m 8s
build (17, gcr.io/etcd-development/etcd:v3.4.27) / build	8m 9s
build (17, gcr.io/etcd-development/etcd:v3.4.27) / build	8m 9s
build (11, gcr.io/etcd-development/etcd:v3.4.27) / build	7m 39s
build (11, gcr.io/etcd-development/etcd:v3.4.27) / build	7m 39s
build (17, gcr.io/etcd-development/etcd:v3.5.9) / build	8m 11s
build (17, gcr.io/etcd-development/etcd:v3.5.9) / build	8m 11s
build (21, gcr.io/etcd-development/etcd:v3.4.27) / build	8m 9s
build (21, gcr.io/etcd-development/etcd:v3.4.27) / build	8m 9s
build (21, gcr.io/etcd-development/etcd:v3.5.9) / build	8m 34s
build (21, gcr.io/etcd-development/etcd:v3.5.9) / build	8m 34s
	1h 41m 31s

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