isDefineAMD fails when using arrow functions

[roguib]

Add the following test in test/tests.js. Run npm test and notice that fails:

assert.ok(check("define(['jquery'] , ($) => { class A {} return A;});", types.isDefineAMD));

Checkout version 2.7.0, which has commit hash of f5c2a2c. Execute the same test and notice that now it passes. This might be a regression of #18, although I'm not sure about it.

[XhmikosR]

I have quickly prepared a patch, please check it out main...xmr/fix-amd

I have another branch that will conflict with any changes in main so maybe I'll need to hold off on this for a while.

Or maybe decide to merge the fix and cut a new patch version, but I'm not very familiar with the code base, apart from tests passing. And leave the other branch for later.