* fix MSVC compiler shared library issues - mostly around 'extern const'
* add vcpkg install getopt to appveyor-windows.yml
show appveyor where to get getopt from vcpkg (non-static lib to avoid LGPL violation)
* add missing else case in lsquic_shared_support.h for windows static lib path
* have cmake spit out it's version
have cmake copy dependent dlls to build dir for tests on windows (getopt.dll)
* copy getopt.dll dep for tests
added commented version that requires >= 3.21 but handles any dll deps
* try caching boringssl dir to reduce CI build time since it's always same commit specified in config file
define VCPKG_ROOT in env since I can't seem to find it by VCPKG_ROOT or VCPKG_INSTALLED_DIR in appveyor's cmake v3.16 + vcpkg
* make windows cache dependent on yml and cmd
* sync up with changes to ls-qpack
- [API] New knob to set outgoing packet batch size.
- Aborted connection now become tickable immediately.
- Abort connection when HTTP/3 frame cannot be opened (can only happen
when malloc fails).
- [FEATURE] QUIC and HTTP/3 Internet Draft 28 support.
- [BUGFIX] Ignore Retry packets after other packets are decrypted
successfully.
- [BUGFIX] Transport parameter decoding: CID no longer has 4-byte
length minimum.
- http_client: fix and optimize lsxpack_header allocator.
- Drop support for Internet Draft 25.
