Update sonarqube-fastlane.md (#179)

Typo in the example. (courtesy of @croustibapt)

Author: ZeWaren

docs/sonarqube-fastlane.md

@@ -9,7 +9,7 @@ Then add the following lane.
 lane :metrics do
     scan(scheme: "[SCHEME]", code_coverage: true, derived_data_path: "./DerivedData", output_directory: "./reports")
     slather(cobertura_xml: true, jenkins: true, scheme: "[SCHEME]", build_directory: "./DerivedData", output_directory: "./reports", proj: "./[PROJECT].xcodeproj")
-    lizard(source_folder: "[SOURCE_FOLDER]", language: "swift", export_type: "xml", report_file: "report/lizard-report.xml")
+    lizard(source_folder: "[SOURCE_FOLDER]", language: "swift", export_type: "xml", report_file: "reports/lizard-report.xml")
     swiftlint(output_file: "./reports/swiftlint.txt", ignore_exit_status: true)
     sonar
 end