channels/*-4.5: Add 4.4.6 to fast-4.5 and stable-4.5

It has been in stable-4.4 since dc06ce1 (Enable 4.4.6 in stable
channel(s), 2020-05-27, #263) landed.  Promoting into fast/stable
channels for 4.5 makes it clear that we support 4.4.6 regardless of
whether a cluster is interested in 4.5 update recommendations or not.

Author: wking

channels/candidate-4.5.yaml

@@ -1,5 +1,4 @@
 name: candidate-4.5
-versions: 
+versions:
 - 4.4.6
-
 - 4.5.0-rc.1

channels/fast-4.5.yaml

@@ -1,2 +1,3 @@
 name: fast-4.5
-versions: []
+versions:
+- 4.4.6

channels/stable-4.5.yaml

@@ -1,2 +1,3 @@
 name: stable-4.5
-versions: []
+versions:
+- 4.4.6