Receiver.packet_history_window memory leak

[dholroyd]

Data is pushed into the Receiver.packet_history_window here,

srt-rs/srt-protocol/src/protocol/receiver/mod.rs

Line 491 in d5120eb

self.packet_history_window.push((data.seq_number, ts_now));

However there doesn't seem to be any code to remove items from this Vec, so we eventually run out of memory.

[russelltg]

Duplicate #40

Thanks for the report!