Netdryrun 0.2.0: SONiC, Arista EOS, record and the verdict corpus¶

Two more network operating systems, baselines without writing checks by hand, and the first published corpus.

SONiC (docker-sonic-vs) and Arista EOS (cEOS-lab, bring your own image) drivers.
netdryrun record snapshots a known-good lab into a netdryrun.yml baseline, so you don't write checks by hand.
Failure scenarios: link_down and node_isolated, with links always restored.
GitHub Action pr-comment: true: one PR comment with the verdict and the evidence for each failed check.
The verdict corpus: 30 pre-registered cases comparing ping-only, session-only and Netdryrun checks, losses published.