Update to transport/v5

Change path to v4

Ignore reserved bits in ERROR-CODE (#286)

Fix UnknownAttributes encoding to match RFC 5389 (#280)

Pion uses 4 bytes per attribute type instead of 2 as specified in
RFC 5389. On send side it is not so bad, other STUN peer will see extra
zero attributes, so most likely it will be able to deal with this.
In opposite direction there is a data loss, half of received attributes
is silently discarded when pion decodes received packet.

Upgrade dtls to fix compatibility with firefox

Update module github.com/pion/dtls/v3 to v3.1.3

Fix panic on short XOR-MAPPED-ADDRESS value

XORMappedAddress.GetFromAs read value[0:2] to decode the address
family before validating the attribute value length. A malformed STUN
message carrying an XOR-MAPPED-ADDRESS attribute with a 0-length value
at the end of a tightly allocated buffer triggered a slice-bounds
runtime panic, since the value slice had no spare capacity to re-slice
into.

Move the length check ahead of the first read so a short value returns
io.ErrUnexpectedEOF instead of panicking. This is remotely triggerable
on normal STUN/ICE Binding-response parsing paths.

Reported by Karolina GORNA

Reported-By: karolina.gorna@ledger.com
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Keep DTLS configs until API change

Upgrade to pion/transport/v4

Add STUN attributes for DTLS-in-STUN (SPED)

aѕ defined in
  https://www.iana.org/assignments/stun-parameters/stun-parameters.xml

The name drops the META which is likely to happen after standardization.