* updating netcore and variables

* updating from NETCOREAPP2_1 to NETCOREAPP;
adding netcoreapp3.1 as targetframework as well

* updating yml build;
updating package condition

* refactor yml

reorganize sections to be descending frameworks (v3, v2)
add comments.
remove hardcoded framework versions in favor of version wildcard

* updating yml

* testing full path in yml

* adding detailed logging to yml

* adding netcore3.1 to linux environment

Co-authored-by: Timothy Mothra <tilee@microsoft.com>

* Renaming DiagnosticSourceListener.netcoreapp10 to DiagnosticSourceListener.Tests;
enabled netcoreapp1.1, netcoreapp2.1, netcoreapp3.1;
changed yml file to test workerservice to netcoreapp3.1

* merging Log4NetAppender.Tests;
adding netcoreapp1.1, 2.1 and 3.1;
updating Logging.sln (removing old project / adding new one)

* Merging NLogTarget.Tests

* Merging TraceListener.Tests

* updating AssemblyInfo and AssemblyProduct