Bump stryker to 4.7.0

Update to the latest release of dotnet-stryker.

Author: martincostello

.config/dotnet-tools.json

@@ -24,7 +24,7 @@
       "rollForward": false
     },
     "dotnet-stryker": {
-      "version": "4.5.1",
+      "version": "4.7.0",
       "commands": [
         "dotnet-stryker"
       ],
@@ -58,4 +58,4 @@
       "rollForward": false
     }
   }
-}
+}