updated GitHub action

updated README

Merge pull request iayti#36 from iayti/update/dependency

Updated all packages.

README updated.

Delete dotnet_2.yml

Merge pull request iayti#23 from iayti/feature/CAS-7_SampleService

Feature/cas 7 sample service

Merge pull request iayti#22 from iayti/feature/CAS-18_Authorization

Feature/cas 18 authorization

dotnet-core github action workflow removed.

refactore usings.

1) added District tests.

2) test bug fixed.