[avro] Support all default types for avro schema's record field

[yongkyunlee]

Which issue does this PR close?

Closes #8209

Rationale for this change

In the Field struct definition

/// A field within a [`Record`]
#[derive(Debug, Clone, PartialEq, Eq, Serialize, Deserialize)]
pub struct Field<'a> {
    /// Name of the field within the record
    #[serde(borrow)]
    pub name: &'a str,
    /// Optional documentation for this field
    #[serde(borrow, default)]
    pub doc: Option<&'a str>,
    /// The field's type definition
    #[serde(borrow)]
    pub r#type: Schema<'a>,
    /// Optional default value for this field
    #[serde(borrow, default)]
    pub default: Option<&'a str>,
}

type is of type Schema whereas default is of type str. The default should be supported for all types (e.g. int, array, map, nested record), so we should make it more lenient.

More details on reproduction is mentioned in the Github Issue.

What changes are included in this PR?

Relaxation of default type of avro scheam Field.

Are these changes tested?

Added a unit test.

Are there any user-facing changes?

It affects pub struct Field of arrow-avro package, but the impact should be minimal as the default attribute is not being used.

[alamb]

@jecsand838 do you have time to review this PR?

[jecsand838]

@yongkyunlee Thanks for making this contribution!

LMGTM, just had one nit.

[yongkyunlee]

Thanks! Addressed the comment
@alamb @jecsand838

[alamb]

Thanks @yongkyunlee @jecsand838 and @mbrobbel 🚀

[mbrobbel]

Shouldn't we wait until after 56.2.0 (because this is a breaking change)?

[mbrobbel]

Shouldn't we wait until after 56.2.0 (because this is a breaking change)?

Ah, I just learned this isn't public yet.

[alamb]

Shouldn't we wait until after 56.2.0 (because this is a breaking change)?

Ah, I just learned this isn't public yet.

Indeed -- but thank you for the review. I think the idea is that we'll bash on with new feature development / breaking API changes, etc until we are satisfied this crate is ready, and then we'll start subjecting it to the same API versioning as other crates.