fix: Warning missing lexical-binding cookie in Eask-file

[jcs090218]

Attempt to fix warning:

eask compile
Warning (files): Missing ‘lexical-binding’ cookie in "~/work/company-fuzzy/company-fuzzy/Eask".
You can add one with ‘M-x elisp-enable-lexical-binding RET’.
See ‘(elisp)Selecting Lisp Dialect’ and ‘(elisp)Converting to Lexical Binding’
for more information.
Compiling /home/runner/work/company-fuzzy/company-fuzzy/company-fuzzy.el... done ✓

Source: https://github.com/jcs-elpa/company-fuzzy/actions/runs/14594887284/job/40938348405#step:5:76