Re-add net48, run net6.0 in ci

Author: jviau

.github/workflows/validate-build.yml

@@ -42,7 +42,7 @@ jobs:
       run: dotnet build $solution --configuration $config --no-restore -p:FileVersionRevision=$GITHUB_RUN_NUMBER
 
     - name: Test
-      run: dotnet test $solution --configuration $config --no-build --verbosity normal
+      run: dotnet test $solution --framework net6.0 --configuration $config --no-build --verbosity normal
 
     - name: Pack
       run: dotnet pack $solution --configuration $config --no-build

test/Client/Grpc.Tests/Client.Grpc.Tests.csproj

@@ -1,8 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
-    <!-- <TargetFrameworks>net6.0;net48</TargetFrameworks> -->
-    <TargetFramework>net6.0</TargetFramework>
+    <TargetFrameworks>net6.0;net48</TargetFrameworks>
   </PropertyGroup>
 
   <ItemGroup>

test/Worker/Grpc.Tests/Worker.Grpc.Tests.csproj

@@ -1,8 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
-    <!-- <TargetFrameworks>net6.0;net48</TargetFrameworks> -->
-    <TargetFramework>net6.0</TargetFramework>
+    <TargetFrameworks>net6.0;net48</TargetFrameworks>
   </PropertyGroup>
 
   <ItemGroup>