[BEAM-12047] Updates CHANGES.md to mention the URN convention (#15845)
[BEAM-12047] Updates CHANGES.md to mention the URN convention (#15845)

* Updates CHANGES.md to mention the URN convention

* Updated text
lukecwik/incubator-beam,chamikaramj/beam,chamikaramj/beam,lukecwik/incubator-beam,robertwb/incubator-beam,chamikaramj/beam,lukecwik/incubator-beam,apache/beam,robertwb/incubator-beam,chamikaramj/beam,apache/beam,apache/beam,robertwb/incubator-beam,apache/beam,chamikaramj/beam,robertwb/incubator-beam,chamikaramj/beam,apache/beam,lukecwik/incubator-beam,apache/beam,lukecwik/incubator-beam,apache/beam,apache/beam,lukecwik/incubator-beam,chamikaramj/beam,lukecwik/incubator-beam,robertwb/incubator-beam,apache/beam,chamikaramj/beam,robertwb/incubator-beam,chamikaramj/beam,lukecwik/incubator-beam,robertwb/incubator-beam,apache/beam,robertwb/incubator-beam,lukecwik/incubator-beam,chamikaramj/beam,robertwb/incubator-beam,lukecwik/incubator-beam,robertwb/incubator-beam,apache/beam