remove ncoretab dependency.

src/DotNetCore.CAP/CAP.Options.cs

@@ -15,23 +15,12 @@ namespace DotNetCore.CAP
         /// </summary>
         public const int DefaultPollingDelay = 8;
 
-        /// <summary>
-        /// Default value for CAP job.
-        /// </summary>
-        public const string DefaultCronExp = "* * * * *";
-
         public CapOptions()
         {
-            CronExp = DefaultCronExp;
             PollingDelay = DefaultPollingDelay;
             Extensions = new List<ICapOptionsExtension>();
         }
 
-        /// <summary>
-        /// Corn expression for configuring retry cron job. Default is 1 min.
-        /// </summary>
-        public string CronExp { get; set; }
-
         /// <summary>
         /// Productor job polling delay time. Default is 8 sec.
         /// </summary>

src/DotNetCore.CAP/DotNetCore.CAP.csproj

@@ -20,7 +20,6 @@
     <PackageReference Include="Microsoft.Extensions.DependencyInjection.Abstractions" Version="1.1.1" />
     <PackageReference Include="Microsoft.Extensions.Logging.Abstractions" Version="1.1.2" />
     <PackageReference Include="Microsoft.Extensions.DependencyInjection" Version="1.1.1" />
-    <PackageReference Include="ncrontab" Version="3.3.0" />
     <PackageReference Include="Newtonsoft.Json" Version="10.0.3" />
     <PackageReference Include="System.Data.Common" Version="4.3.0" />
     <PackageReference Include="System.Threading.ThreadPool" Version="4.3.0" />