chore: Bump fable from 5.0.0-rc.6 to 5.0.0-rc.7 (#241)

Author: dependabot[bot]

.config/dotnet-tools.json

@@ -10,7 +10,7 @@
       "rollForward": false
     },
     "fable": {
-      "version": "5.0.0-rc.6",
+      "version": "5.0.0-rc.7",
       "commands": [
         "fable"
       ],