fix dataitem verification

[nikooo777]

Currently, arbundles implementations don't correctly implement the ANS-104 spec.

Specifically: https://github.com/ArweaveTeam/arweave-standards/blob/master/ans/ANS-104.md#21-verifying-a-dataitem

A DataItem is valid iff.1:

id matches the signature (via SHA-256 of the signature)
signature matches the owner's public key
tags are all valid
an anchor isn't more than 32 bytes

A tag object is valid iff.:

there are <= 128 tags
each key is <= 1024 bytes
each value is <= 3072 bytes
only contains a key and value
both the key and value are non-empty strings

This PR aims at successfully verifying dataitems with tags together exceeding 4092 bytes in size but remaining within the per-tag threshold.
It also adds anchor validation.

As bonus point, a couple of vulnerable dependencies are updated.

[fedellen]

While this does respect the documented spec, there are existing apps and integrations using empty strings on name and value through Turbo

Suggested change

	if (nameLen === 0 || nameLen > MAX_TAG_KEY_LENGTH) {
	return false;
	}
	if (valueLen === 0 || valueLen > MAX_TAG_VALUE_LENGTH) {
	return false;
	}
	if nameLen > MAX_TAG_KEY_LENGTH) {
	return false;
	}
	if (valueLen > MAX_TAG_VALUE_LENGTH) {
	return false;
	}

[nikooo777]

I appreciate the input.
Apparently there are more instances of other projects violating the spec, so I think the only real change that stands a chance of getting eventually merged is going to be one where we simply check that there are at most 128 tags and each tag (name+val) is 4KB at most.

[nikooo777]

closed in favor of #6