feat: Add attributes to ABIFunction

[anton-trunov]

This is needed for FuelLabs/sway#3450 and for #742 eventually.

Spec issue: FuelLabs/fuel-specs#446
Compiler change: FuelLabs/sway#3450

Correction: the explanation below is only true at the parser level, the distinction between foo and foo() disappears later in the pipeline, so I changed the type of arguments field to Vec<String>.

The Option<Vec<String>> in

pub struct Attribute {
     pub name: String,
     pub arguments: Option<Vec<String>>,
 }

is needed because in Sway a parameterless attribute foo and an attribute with empty parameter list foo() are not the same.

[segfault-magnet]

This seems to be a breaking change. The CI is complaining:

SerdeJson(Error("missing field attributes", line: 43, column: 5))

I haven't checked more closely but it seems that the way we're adding this is breaking backward compatibility -- i.e. we won't be able to release until the compiler starts providing the attribute field. Do you have an ETA this?

If it's too long we should probably look into guiding serde to default-populate the field if it is not present in the json file and still remain backward compatible.

Also, unless deserialization is altered, you'll probably need a feature flag in forc so that it may generate the appropriate json files with the attributes present, otherwise the CI can't generate the abi json files needed for our e2e tests.

[anton-trunov]

@segfault-magnet I made the function attributes optional -- it turns out to be too hard to introduce a breaking change like an obligatory field because of close coupling of the Sway and Fuels-rs repos.

[iqdecay]

lgtm