Add QUIC to the list of well known network transports

[lmolkova]

Fixes #1237

Changes

QUIC is a transport-level protocol based on UDP.

QUIC (/kwɪk/) is a general-purpose[1] transport layer[2] network protocol

It's worth adding it to the list of well-know values of network.transport.

Adding it as experimental with assumption that nothing stable depends on it.

Given it's a well-recognized name listed in RFC, it does not seem to be a problem to stabilize the constant name whenever the need comes.

Merge requirement checklist

• CONTRIBUTING.md guidelines followed.
• Change log entry added, according to the guidelines in When to add a changelog entry.
  • If your PR does not need a change log, start the PR title with [chore]
• schema-next.yaml updated with changes to existing conventions.