upgrade nuget and upgrade framework to netstandard 2.1

src/DotNetCore.CAP.MySql/DotNetCore.CAP.MySql.csproj

@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
-    <TargetFramework>netstandard2.0</TargetFramework>
+    <TargetFramework>netstandard2.1</TargetFramework>
     <AssemblyName>DotNetCore.CAP.MySql</AssemblyName>
     <PackageTags>$(PackageTags);MySQL</PackageTags>
   </PropertyGroup>
@@ -12,10 +12,10 @@
   </PropertyGroup>
 
   <ItemGroup>
-    <PackageReference Include="Dapper" Version="1.60.6" />
-    <PackageReference Include="Microsoft.EntityFrameworkCore" Version="2.2.0" />
-    <PackageReference Include="Microsoft.EntityFrameworkCore.Relational" Version="2.2.0" />
-    <PackageReference Include="MySqlConnector" Version="0.56.0" />
+    <PackageReference Include="Dapper" Version="2.0.30" />
+    <PackageReference Include="Microsoft.EntityFrameworkCore" Version="3.0.0" />
+    <PackageReference Include="Microsoft.EntityFrameworkCore.Relational" Version="3.0.0" />
+    <PackageReference Include="MySqlConnector" Version="0.60.3" />
   </ItemGroup>
 
   <ItemGroup>