Fix broken fuzz targets

[CUB3D]

Fixes the following fuzz targets:

• amf0_header
• amf0_element_array
• amf3_string
• amf3_int_unsigned
• amf3_int_signed

Removes the following trivial fuzz targets:

• amf0_length
• amf0_string
• amf0_signature
• amf0_version
• amf0_bool
• amf0_number
• amf0_string
• amf0_long_string

All fuzz cases now build and run, however amf3_body still fails due to issues with Rc

Gates amf3 behind feature "amf3" so the amf0 fuzzer doesn't start wandering off, default is enabled

Updates dev/fuzzing deps
Fixes workspace resolver warning

[Dinnerbone]

Gates amf3 behind feature "amf3" so the amf0 fuzzer doesn't start wandering off, default is enabled

That's kind of a problem with our structure atm; we need to be able to tell something to stick to amf0.

In actual spec, amf3 serialization writes amf0 by default and only elevates to amf3 as-required. amf0 serializers shouldn't be able to upgrade to amf3

[CUB3D]

I think these are two different problems, this is trying to fix the issue of TypeMarker::AMF3 tags sending the amf0 fuzzer off down the amf3 path when decoding, which should be getting coverage from the amf3 fuzzer anyway.
I do remember having to make a lot of guesses about the serialization side of things, evidently quite a few were wrong