Gate builds using .net 5 SDK (#63)

* build .net 5

* tests target 5

Author: bitfaster

.github/workflows/dotnet-core.yml

@@ -16,7 +16,7 @@ jobs:
     - name: Setup .NET Core
       uses: actions/setup-dotnet@v1
       with:
-        dotnet-version: 3.1.101
+        dotnet-version: 5.0.100
     - name: Install dependencies
       run: dotnet restore
     - name: Build

BitFaster.Caching.UnitTests/BitFaster.Caching.UnitTests.csproj

@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
-    <TargetFramework>netcoreapp3.1</TargetFramework>
+    <TargetFramework>net5.0</TargetFramework>
   </PropertyGroup>
 
   <ItemGroup>