Use Asp.Net Core 2.1 in .NET Framework NSwag.Console (RicoSuter#3289)

Asp.Net Core 2.1 is only supported version for .NET Framework 4 as of today.
Asp.Net Core 2.2 is EOL as of December 23, 2019

Co-authored-by: Oleg Deribas <olegd@superoffice.com>

Merge pull request RicoSuter#3255 from RicoSuter/master

Release v13.10.1

Merge pull request RicoSuter#3251 from RicoSuter/master

Release v13.10.0

Merge pull request RicoSuter#3185 from RicoSuter/master

Release v13.9.4

Merge pull request RicoSuter#3176 from RicoSuter/master

Release v13.9.3

Merge pull request RicoSuter#3169 from RicoSuter/master

v13.9.2, fix NPM package

Merge pull request RicoSuter#3164 from RicoSuter/master

Release v13.9.1

Merge pull request RicoSuter#3157 from RicoSuter/master

Release v13.9.0, update NJS to v10.3.0 (.NET 5.0)

Merge pull request RicoSuter#3084 from RicoSuter/master

Release v13.8.2

Merge pull request RicoSuter#3080 from RicoSuter/master

Release v13.8.1