services/horizon: Update changelog for Horizon v22 release #4330

Job	Run time
Test (and push) verify-range image	2m 10s
Integration tests (ubuntu-20.04, 1.21, 12, 21)	53m 24s
Integration tests (ubuntu-20.04, 1.21, 12, 22)	54m 19s
Integration tests (ubuntu-20.04, 1.21, 16, 21)	54m 13s
Integration tests (ubuntu-20.04, 1.21, 16, 22)	55m 3s
Integration tests (ubuntu-20.04, 1.22, 12, 21)	54m 7s
Integration tests (ubuntu-20.04, 1.22, 12, 22)	54m 2s
Integration tests (ubuntu-20.04, 1.22, 16, 21)	54m 6s
Integration tests (ubuntu-20.04, 1.22, 16, 22)	54m 47s
Integration tests (ubuntu-22.04, 1.21, 12, 21)	48m 16s
Integration tests (ubuntu-22.04, 1.21, 12, 22)	52m 56s
Integration tests (ubuntu-22.04, 1.21, 16, 21)	53m 59s
Integration tests (ubuntu-22.04, 1.21, 16, 22)	55m 6s
Integration tests (ubuntu-22.04, 1.22, 12, 21)	50m 50s
Integration tests (ubuntu-22.04, 1.22, 12, 22)	51m 30s
Integration tests (ubuntu-22.04, 1.22, 16, 21)	53m 15s
Integration tests (ubuntu-22.04, 1.22, 16, 22)	55m 49s
	14h 17m 52s

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