Discard legacy Gem::Version syntax

[#71439980]

Signed-off-by: Mark Rushakoff <mrushakoff@pivotallabs.com>
content_migrations version also bumped

[#71439980]

Signed-off-by: Mark Rushakoff <mrushakoff@pivotallabs.com>
picks the sole .yml in content_migrations

[#71439980]

Signed-off-by: Mark Rushakoff <mrushakoff@pivotallabs.com>