main/re2c: upgrade to 3.0
https://re2c.org/releases/release_notes.html#release-3-0
PS python3
is required to run tests https://re2c.org/build/build.html but bash
is not
usr/bin/
usr/bin/re2c
usr/bin/re2go
+usr/bin/re2rust
Edited by Andy Postnikov