Consider int zero to be an invalid value in property value

This matches the same behaviour for the TimeSpan property check

Author: Plasma

src/Hangfire.PostgreSql/PostgreSqlStorageOptions.cs

@@ -129,7 +129,7 @@ private static void ThrowIfValueIsNotPositive(TimeSpan value, string fieldName)
 
         private static void ThrowIfValueIsNotPositive(int value, string fieldName)
         {
-            if (value < 0)
+            if (value <= 0)
 		        throw new ArgumentException($"The {fieldName} property value should be positive. Given: {value}.");
         }
     }