THRIFT-4990 Switch to .NET core 3.0
Client: netstsd
Patch: Jens Geyer

This closes #1909
diff --git a/lib/netstd/README.md b/lib/netstd/README.md
index 88ba73a..74f5ed8 100644
--- a/lib/netstd/README.md
+++ b/lib/netstd/README.md
@@ -11,7 +11,7 @@
 - Build with scripts
 
 ## How to build on Unix/Linux
-- Ensure you have .NET SDK >= 2.0 installed, or use the [Ubuntu docker image](../../build/docker/README.md)
+- Ensure you have .NET Core SDK 3.0 installed, or use the [Ubuntu docker image](../../build/docker/README.md)
 - Follow common automake build practice: `./ bootstrap && ./ configure && make`
 
 ## Known issues
diff --git a/lib/netstd/Tests/Thrift.IntegrationTests/Thrift.IntegrationTests.csproj b/lib/netstd/Tests/Thrift.IntegrationTests/Thrift.IntegrationTests.csproj
index 381d8aa..c3cdc11 100644
--- a/lib/netstd/Tests/Thrift.IntegrationTests/Thrift.IntegrationTests.csproj
+++ b/lib/netstd/Tests/Thrift.IntegrationTests/Thrift.IntegrationTests.csproj
@@ -19,7 +19,7 @@
   -->
 
   <PropertyGroup>
-    <TargetFramework>netcoreapp2.0</TargetFramework>
+    <TargetFramework>netcoreapp3.0</TargetFramework>
     <AssemblyName>Thrift.IntegrationTests</AssemblyName>
     <PackageId>Thrift.IntegrationTests</PackageId>
     <OutputType>Exe</OutputType>
diff --git a/lib/netstd/Tests/Thrift.PublicInterfaces.Compile.Tests/Thrift.PublicInterfaces.Compile.Tests.csproj b/lib/netstd/Tests/Thrift.PublicInterfaces.Compile.Tests/Thrift.PublicInterfaces.Compile.Tests.csproj
index 58f61a2..498191f 100644
--- a/lib/netstd/Tests/Thrift.PublicInterfaces.Compile.Tests/Thrift.PublicInterfaces.Compile.Tests.csproj
+++ b/lib/netstd/Tests/Thrift.PublicInterfaces.Compile.Tests/Thrift.PublicInterfaces.Compile.Tests.csproj
@@ -19,7 +19,7 @@
   -->
 
   <PropertyGroup>
-    <TargetFramework>netcoreapp2.0</TargetFramework>
+    <TargetFramework>netcoreapp3.0</TargetFramework>
     <AssemblyName>Thrift.PublicInterfaces.Compile.Tests</AssemblyName>
     <PackageId>Thrift.PublicInterfaces.Compile.Tests</PackageId>
     <GenerateAssemblyConfigurationAttribute>false</GenerateAssemblyConfigurationAttribute>
diff --git a/lib/netstd/Tests/Thrift.Tests/Thrift.Tests.csproj b/lib/netstd/Tests/Thrift.Tests/Thrift.Tests.csproj
index 434424d..b060182 100644
--- a/lib/netstd/Tests/Thrift.Tests/Thrift.Tests.csproj
+++ b/lib/netstd/Tests/Thrift.Tests/Thrift.Tests.csproj
@@ -18,7 +18,7 @@
     under the License.
   -->
   <PropertyGroup>
-    <TargetFramework>netcoreapp2.0</TargetFramework>
+    <TargetFramework>netcoreapp3.0</TargetFramework>
   </PropertyGroup>
   <ItemGroup>
     <PackageReference Include="CompareNETObjects" Version="4.58.0" />
diff --git a/lib/netstd/Thrift/Thrift.csproj b/lib/netstd/Thrift/Thrift.csproj
index 5d8a9c3..783b9e9 100644
--- a/lib/netstd/Thrift/Thrift.csproj
+++ b/lib/netstd/Thrift/Thrift.csproj
@@ -19,7 +19,7 @@
   -->
 
   <PropertyGroup>
-    <TargetFramework>netstandard2.0</TargetFramework>
+    <TargetFramework>netstandard2.1</TargetFramework>
     <AssemblyName>Thrift</AssemblyName>
     <PackageId>Thrift</PackageId>
     <AutoGenerateBindingRedirects>true</AutoGenerateBindingRedirects>