New version of Microsoft.ICU.ICU4C.Runtime

[imranbaloch]

The latest version of Microsoft.ICU.ICU4C.Runtime is 68.2.0.9 https://www.nuget.org/packages/Microsoft.ICU.ICU4C.Runtime/68.2.0.9 last update (9/27/2021) but I see ICO new version is 73 https://icu.unicode.org/download/73. Is Microsoft.ICU.ICU4C.Runtime is still maintained or I am missing something?

[svick]

See also #120.