Update ls-qpack to 2.3.0

Release 3.0.4

[WIP] use vcpkg for getopt; build windows shared lib enhancements (#350)

* 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

Update ls-qpack to v2.2.2 .

Use ls-qpack v2.2.1

API: use lsxpack_header v206

Update ls-hpack to v2.2.0 and ls-qpack to v2.2.0 for lsxpack_header v206

(Not a typo: both libraries now happen to have the same version number.)

Release 2.14.4

- [BUGFIX] Heed es_rw_once for pushed HTTP/3 streams.
- [BUGFIX] IETF client: set correct flags on bidirectional streams.
- [BUGFIX] Generate Cancel Stream QPACK instructions for abandoned
streams.
- [BUGFIX] Do not call header callbacks after stream is closed.
- Use ls-qpack 2.1.1

Release 2.14.3

- [BUGFIX] gQUIC: pass correct stream to hsi_create_header_set() callback.
- [BUGFIX] Use ls-hpack 2.1.1
- Improve stream code readability.
- Use ls-qpack 2.0.5

Release 2.14.2

- [BUGFIX] Use ls-qpack 2.0.4
- [BUGFIX] Honor max packet size on the client and when path changes.
- http_server: fix prepare_decode() function.

Release 2.14.0

- [API] Use lsxpack_header structure to send HTTP headers.
- [OPTIMIZATION] nocopy's readable_bytes() function.
- http_server: fix typo in error message
- Use ls-hpack 2.1.0.
- Use ls-qpack 2.0.0.

Release 2.13.0

- [API] Use lsxpack_header structure to process incoming headers.
- [BUGFIX] Fix assertion when zero-padding Initial packet.
- [BUGFIX] Use idle timeout before we learn of peer's value.
- Use ls-hpack 2.0.0 -- has lsxpack_header changes.
- Use ls-qpack 0.14.0 -- new, common with ls-hpack, XXH seed (not used yet).
- Code cleanup: prefix exported functions with "lsquic_".

Release 2.9.0

- [API] Drop support for Q039.
- Improve ACK-queuing logic. Send an ACK once in a while if
peer keeps on sending non-ack-eliciting packets.
- Improve Alt-Svc string: Q050 and later are not included in
the old-style "quic" string.
- Send stateless resets if connection could not be promoted.
- Schedule MAX_DATA if needed when DATA_BLOCKED is received.
- Use ls-qpack 0.11.2 -- needed for server push optimization.
- Code cleanup: handle some error cases, improve logging.

Use ls-qpack v0.11.1

Use ls-qpack v0.11.0

Release 2.5.0

- [API] lsquic_engine_connect() can now be passed QUIC version to use.
- [OPTIMIZATION] Queue opportunistic ACKs if there is data to be sent.
- [BUGFIX] Don't evict streams from priority iterator if there is
only one queue.
- [OPTIMIZATION, BUGFIX] Several other optimizations and bug fixes.
- Use ls-qpack v0.10.7.

Release 2.4.10: fix regression in 2.4.9, use ls-qpack 0.10.6

Release 2.4.8

- [OPTIMIZATION, BUGFIX] Use ls-qpack v0.10.5.

Release 2.4.5

- [OPTIMIZATION]: flush encoder stream only when necessary.
- [BUGFIX] Use ls-qpack v0.10.2 for new API -- and for a bug fix.
- [BUGFIX] Typo in IETF conn SETTINGS writer.
- Use latest BoringSSL.

Use ls-qpack v0.10.0

Release 2.2.0: server included, ID-22 supported (#76)