chore: actually release v1.32.0-rc3 (#521)

I merged #520 before I noticed that it didn't actually bump the version
number (probably wasn't ready yet, oops).

Author: Stebalien

version.json

@@ -1,3 +1,3 @@
 {
-  "version": "v1.32.0-rc2"
+  "version": "v1.32.0-rc3"
 }