Merge branch 'update-script' into 'master'

add script to update/maintain channel lists

See merge request !5
3 jobs for master in 10 minutes and 46 seconds (queued for 3 seconds)
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Status Name Job ID Coverage
  Build And Test
passed ligo-channel-completion:buster #247713

00:01:21

passed ligo-channel-completion:jessie #247715

00:10:45

passed ligo-channel-completion:stretch #247714

00:01:12