Correct legacy import `assert` syntax
(node:2417313) V8: file:///home/ckie/git/svelte-persistent-store/rollup.config.mjs:6 'assert' is deprecated in import statements and support will be removed in a future version; use 'with' instead
Allows use of my usual Node.js v24, previously only worked when i tested on v20.
I will have to pull some stats on the Node version usage. If the quantity of users that use an old version of Node that don't the support the new syntax is very small, the change can be done
(but I will probably make a v3.0.0, because the lib will not be retro-compatible)
SGTM! Just to clarify since I realize it was ambiguous in the original text, the old syntax is unsupported in recent node versions.