Get dotnet version from global.json in github workflows

[m-ringler]

Description

• In the github workflows that build czishrink, get the dotnet SDK version from global.json. This will prevent them from breaking whenever a new release of the dotnet sdk becomes available in github.

• Add temporary workaround for vcpkg issue [boost-cmake] Build error on x64-windows (download error on GH CI) microsoft/vcpkg#41199

Type of change

• Bug fix (non-breaking change which fixes an issue)

How Has This Been Tested?

Run workflows in PR.

Checklist

• I followed the Contributing Guidelines.
• I did a self-review.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 78.03%. Comparing base (23314db) to head (2ac8dfb).
Report is 1 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main      #74   +/-   ##
=======================================
  Coverage   78.03%   78.03%           
=======================================
  Files          59       59           
  Lines        1917     1917           
  Branches      120      120           
=======================================
  Hits         1496     1496           
  Misses        397      397           
  Partials       24       24           

Components	Coverage Δ
czicompress	66.75% <ø> (ø)
czishrink	80.84% <ø> (ø)