micrometer-registry-cloudwatch2 is missing from the BOM

[philwebb]

Originally raised by @dreis2211 here, it appears that the micrometer-registry-cloudwatch2 has not been included in the published BOM.

[philwebb]

Sorry, ignore me. There is no micrometer BOM yet.

[shakuzen]

A Micrometer BOM was added as part of #469 which is part of the upcoming 1.3 release.