Update versions; fix CVE-2023-4863 (#13)

* Update versions; fix CVE-2023-4863

This updates minor and major versions:
- upgrading sharp to 0.33 resolves CVE-2023-4863 -- none of the breaking
  changes seem to be an issuse
- upgrading ava from 4 to 6 -- the main breaking change is renaming the
  files to skip watching
- upgrading eslint -- nothing major
- ugrading icojs -- 0.18 just removed support for old node; cannot go to
  0.19 as that switches to ESM

The tests pass, so I think this is good to go.

This closes #10 as it resolves the CVE and updates more versions.

* Bump to 1.1.3