README: import asasertion will be import attributes

[azu]

https://github.com/esm-dev/esm.sh/blob/0dd0ea93d706a0b12b4c4fd890977bd5e17efe2d/README.md?plain=1#L33-L37

import assertions is renamed to import attributes. (assert -> with, but current browsers does not support yet) For more details, see https://github.com/tc39/proposal-import-attributes#history

So, this example will not work in the future. Maybe. At the moment, I do not know what response is appropriate…

[renhiyama]

I would say to close this issue, as currently it works as intended. In the future, there may be or maybe not a chance that assert changes to with keyword. There's a high chance of not changing it given the scenario that a lot of packages and companies have started using/supporting this and changing the keyword in future might seem like breaking the code. The issue can be reopened or a new one can be created in future when that proposal is accepted and is available in most runtimes.