Release 3.1.0

Release 2.27.1

- [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).

Release 2.8.9

- [BUGFIX] Use ls-qpack 0.11.1
- [OPTIMIZATION] Generate random bytes in batches.
- Change loss_bits transport parameter ID to 0x1057 following latest
draft.
- Randomize period with which PINGs are sent to elicit ACKs.
- Some refactoring and code cleanup.