fix dotnet#2309: bump default TFM version to build dotnet-new3 and run tests to 3.1

Author: genalt

src/dotnet-new3/dotnet-new3.csproj

@@ -1,7 +1,7 @@
 <Project ToolsVersion="15.0" Sdk="Microsoft.NET.Sdk">
     <PropertyGroup>
         <Description>Template Instantiation Commands for .NET Core CLI.</Description>
-        <TargetFramework>netcoreapp2.1</TargetFramework>
+        <TargetFramework>netcoreapp3.1</TargetFramework>
         <OutputType>Exe</OutputType>
     </PropertyGroup>
 

test/Microsoft.TemplateEngine.Cli.UnitTests/EndToEndTestBase.cs

@@ -22,7 +22,7 @@ public void Run(string args, params string[] scripts)
 #else
             string configuration = "Release";
 #endif
-            string harnessPath = Path.Combine(dir, "..", "..", "..", "..", "bin", "Microsoft.TemplateEngine.EndToEndTestHarness", configuration, "netcoreapp2.1");
+            string harnessPath = Path.Combine(dir, "..", "..", "..", "..", "bin", "Microsoft.TemplateEngine.EndToEndTestHarness", configuration, "netcoreapp3.1");
             int scriptCount = scripts.Length;
             StringBuilder builder = new StringBuilder();
             builder.Append(scriptCount);

test/Microsoft.TemplateEngine.Cli.UnitTests/Microsoft.TemplateEngine.Cli.UnitTests.csproj

@@ -1,6 +1,6 @@
 <Project Sdk="Microsoft.NET.Sdk">
     <PropertyGroup>
-        <TargetFramework>netcoreapp2.1</TargetFramework>
+        <TargetFramework>netcoreapp3.1</TargetFramework>
         <TestProject>true</TestProject>
     </PropertyGroup>
 

test/Microsoft.TemplateEngine.Cli.UnitTests/TemplateSearchCacheTests.cs

@@ -191,7 +191,7 @@ public async Task CacheSearchLanguageMismatchFilterTest()
             Tags = new Dictionary<string, ICacheTag>(StringComparer.Ordinal)
             {
                 {
-                    "Framework", ResolutionTestHelper.CreateTestCacheTag(new List<string>() { "netcoreapp2.0", "netcoreapp2.1" })
+                    "Framework", ResolutionTestHelper.CreateTestCacheTag(new List<string>() { "netcoreapp2.0", "netcoreapp2.1", "netcoreapp3.1" })
                 },
                 {
                     "language", ResolutionTestHelper.CreateTestCacheTag(new List<string>() { "C#" })

test/Microsoft.TemplateEngine.EndToEndTestHarness/Microsoft.TemplateEngine.EndToEndTestHarness.csproj

@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">
     <PropertyGroup>
         <OutputType>Exe</OutputType>
-        <TargetFramework>netcoreapp2.1</TargetFramework>
+        <TargetFramework>netcoreapp3.1</TargetFramework>
     </PropertyGroup>
 
     <ItemGroup>

test/dotnet-new3.UnitTests/dotnet-new3.UnitTests.csproj

@@ -1,6 +1,6 @@
 <Project Sdk="Microsoft.NET.Sdk" ToolsVersion="15.0">
     <PropertyGroup>
-        <TargetFramework>netcoreapp2.1</TargetFramework>
+        <TargetFramework>netcoreapp3.1</TargetFramework>
         <TestProject>true</TestProject>
     </PropertyGroup>