Release v12.13.0

Modernize plot command with uPlot
- New interactive features: drag-to-zoom, log/linear scale toggle, light/dark theme
- Human-readable latency formatting
- Improved performance and UX

lib,cmd: add Dan as contributor for -connect-to

Previous commit didn't use Co-authored-by properly.

Co-authored-by: Dan Kegel <dank@kegel.com>

lib: use fixed IP selection function

Last release introduced a fixed firstOfEachIPFamily function, but didn't
integrate it.

lib: fix IP selection in DNS caching

Fixes #677

attack: support IPv6 only in DNSCaching

The previous code had a bug that assumed we could always find an IPv4
first.

Fixes #649

Signed-off-by: Tomás Senart <tsenart@gmail.com>

Signed-off-by: Tomás Senart <tsenart@gmail.com>

Signed-off-by: Tomás Senart <tsenart@gmail.com>

Update year range in LICENSE

results: Fix Headers encoding (#507)

* Revert "results: Faster JSON encoding and decoding (#506)"

This reverts commit 3629602.

* results: Fix headers encoding