Bump Incrementalist.Cmd to 1.2.0-beta.1 (#7965)

Author: Arkatufus

.config/dotnet-tools.json

@@ -10,7 +10,7 @@
       "rollForward": true
     },
     "incrementalist.cmd": {
-      "version": "1.1.0",
+      "version": "1.2.0-beta.1",
       "commands": [
         "incrementalist"
       ],