Build both net6.0 and net5.0 by default

Author: alex-kulakov

Directory.Build.props

@@ -42,7 +42,7 @@
     <SuppressNETCoreSdkPreviewMessage>true</SuppressNETCoreSdkPreviewMessage>
     <TargetFrameworks>$(TargetFrameworks)</TargetFrameworks> <!-- the property -->
     <TargetFrameworks Condition="'$(TargetFrameworks)'==''">$(DO_TargetFrameworks)</TargetFrameworks> <!-- env var -->
-    <TargetFrameworks Condition="'$(TargetFrameworks)'==''">net6.0</TargetFrameworks> <!-- fallback to default -->
+    <TargetFrameworks Condition="'$(TargetFrameworks)'==''">net6.0;net5.0</TargetFrameworks> <!-- fallback to default -->
     <LangVersion>9.0</LangVersion>
     <SolutionDir Condition="$(SolutionDir) == ''">$([MSBuild]::EnsureTrailingSlash(
       $([MSBuild]::GetDirectoryNameOfFileAbove('$(MSBuildThisFileDirectory)', 'Orm.sln'))))</SolutionDir>