Bump dotnet-sonarscanner from 5.14.0 to 5.15.0 (#255)

Author: dependabot[bot]

.config/dotnet-tools.json

@@ -3,7 +3,7 @@
   "isRoot": true,
   "tools": {
     "dotnet-sonarscanner": {
-      "version": "5.14.0",
+      "version": "5.15.0",
       "commands": [
         "dotnet-sonarscanner"
       ]