Fixes

• icmpv6: truncate packet to MTU (#807, #808).
• wire/rpl: DAO-ACK DODAG ID was wrongly read (#824).
• socket/tcp: don't panic when calling listen again on the same local endpoint (#841).
• wire/dhcpv4: don't panic when parsing addresses with incorrect amount of bytes (#843).
• iface/ndisc: prevent ndisc when the medium is IP (#865).
• wire/ieee802154: better parsing of security fields. Correctly parse frame type (3 bits instead of 2 bits) (#868).
• wire/ieee802154: better handle address fields for new frame version (#870).
• iface/tcp: don't send TCP RST with unspecified addresses (#867).
• iface: don't handle empty packets (this would panic when reading the IP version) (#866).
• socket/dhcp: Add an upper bound to the renew/rebind timeout in RetryConfig (#835).

Changes

• iface: rewrite IpPacket such that IPv6 packets can contain owned extension headers (#802).
• iface: remove generic T: [u8] in functions. This reduced the server example by 10KB (#810).
• SocketSet: add comment about using static lifetime for SocketSets with owned storage (#813).
• phy/RawSocket: open raw socket with O_NONBLOCK (#817).
• tests/rstest: use rstest for fixture based testing (#823).
• docs/readme: update readme about IEEE802.15.4 and 6LoWPAN (#826).
• wire/ipv6-hbh: IPv6 HBH has owned options instead of references (#827).
• wire/sixlowpan: 6LoWPAN is split into multiple modules (#828).
• sockets: match the behaviour of peek_slice and recv_slice (#834).
• dependencies: update to headpless v0.8 (#853).
• config: make config constants public (#855).
• phy/ieee802154: clarify mtu+=2 for IEEE802.15.4 (#857).
• sockets: recv_slice returns RcvError::Truncated when the length of the slice is smaller than the data received by the socket (#859).
• iface/ipv6: get_source_address uses RFC 6724 for address selection (#864).
• pcap: use IEEE 802.15.4 without FCS for PCAP link types (#874).
• iface: rename IpPacket/Ipv4Packet/Ipv6Packet to Pacet/PacketV4/PacketV4. This is to remove the ambiguity with IpPacket in src/wire/ (#873).
• wire/ndisc: rewrite parse function (3.1KiB -> 1.9KiB) (#878)
• iface: Check IPv6 address after processing HBH (#861)