merge from arlac77/npm-package-template

package.json

chore(package): remove rollup-plugin-json@^4.0.0
chore(package): documentation@^12.1.4
chore(package): add @rollup/plugin-json@^4.0.0
chore(scripts): cover@#overwrite c8 -x 'tests/*/' --temp-directory build/tmp ava && c8 report -r lcov -o build/coverage --temp-directory build/tmp
docs(package): remove keyword null
chore(package): set $.ava.require='esm' as in template
chore(package): set $.ava.files='tests/*-test.mjs' as in template
chore(package): set $.ava.extensions='mjs' as in template