Update worker.config.json set default to 7.4

Author: andystaples

src/worker.config.json

@@ -5,7 +5,7 @@
         "defaultExecutablePath":"dotnet",
         "defaultWorkerPath":"%FUNCTIONS_WORKER_RUNTIME_VERSION%/Microsoft.Azure.Functions.PowerShellWorker.dll",
         "supportedRuntimeVersions":["7", "7.2", "7.4"],
-        "defaultRuntimeVersion": "7.2",
+        "defaultRuntimeVersion": "7.4",
         "sanitizeRuntimeVersionRegex":"\\d+\\.?\\d*"
     }
 }