fix rc build channel (#3139)

Signed-off-by: Jari Kolehmainen <jari.kolehmainen@gmail.com>

build/set_build_version.ts

@@ -33,6 +33,7 @@ function getBuildChannel(): string {
    * Note: it is by design that we don't use `rc` as a build channel for these versions
    */
   switch (versionInfo.prerelease?.[0]) {
+    case "rc":
     case "beta":
       return "beta";
     case undefined: