v1.3.0

1.3.0 is the modified version that requires go1.21 and newer for stdlib based slices, maps, cmp package and clear() builtin.
Use fortio sets v1.2.1 if you need to stay with go1.18-1.20.
(Note you should be using go1.23.8 if you can at the time of this writing, which is what we build with)

What's Changed

• Offer go1.21 and newer based version by @ldemailly in #72

Full Changelog: v1.2.1...v1.3.0