Log Message:
nghttp3: updated to 1.6.0

nghttp3 v1.6.0

Change clang-format options
Fix cmake export
Fix include export
Fix ARM64 __popcnt intrinsics
Refactor qpack reserve_buf
Fix potential overflow
nghttp3_map: Port ngtcp2 changes
Optimize nghttp3_read_varint
Consistent macro comments
clang-format files under fuzz
ispow2: Better fallback implementation
Refactor http on header
Simplify http_request_on_header and http_response_on_header
qpack: Switch on opcode
Do huffman encoding only when the reduction is more than 25%
Optimize nghttp3_check_header_value
Revert "Optimize nghttp3_check_header_value"
cmake: Remove trailing spaces
Optimize nghttp3_check_header_value