Update darling requirement from 0.20 to 0.21

[dependabot]

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⚠️ Dependabot is rebasing this PR ⚠️

Rebasing might not happen immediately, so don't worry if this takes some time.

Note: if you make any changes to this PR yourself, they will take precedence over the rebase.

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Updates the requirements on darling to permit the latest version.

Release notes

Sourced from darling's releases.

v0.21.0

• Potentially breaking: Emit error when an attribute path is present in both attributes and forward_attrs. #336
• Support parsing attributes which contain keywords #238
• Add SpannedValue::into_inner #342
• Add #[darling(derive_syn_parse)] to also impl syn::parse::Parse when deriving FromMeta #285
• Make impl FromMeta for syn::TypePath support both quote-wrapped and bare values #351
• Add util::PreservedStrExpr #346
• Impl UsesTypeParams and UsesLifetimes for WithOriginal #215
• Update error message emitted by <() as FromMeta>::from_list to allow use of () as a #[darling(flatten)] target #353

Changelog

Sourced from darling's changelog.

v0.21.0 (July 10, 2025)

• Potentially breaking: Emit error when an attribute path is present in both attributes and forward_attrs. #336
• Support parsing attributes which contain keywords #238
• Add SpannedValue::into_inner #342
• Add #[darling(derive_syn_parse)] to also impl syn::parse::Parse when deriving FromMeta #285
• Make impl FromMeta for syn::TypePath support both quote-wrapped and bare values #351
• Add util::PreservedStrExpr #346
• Impl UsesTypeParams and UsesLifetimes for WithOriginal #215
• Update error message emitted by <() as FromMeta>::from_list to allow use of () as a #[darling(flatten)] target #353

v0.20.11 (March 28, 2025)

• Support #[darling(with = ...)] on the data field when deriving FromDeriveInput. This allows the use of simpler receiver types, such as a Vec of enum variants.
• Bump version of proc-macro2 to 1.0.86.
• Accept closures for #[darling(with = ...)] on fields in FromDeriveInput, FromMeta, FromField, etc. #309
• Add darling::util::Callable to accept a path or closure as a meta-item expression
• Add #[darling(from_word = ...)] and #[darling(from_none = ...)] to control shorthand and fallback behaviors for structs and enums deriving FromMeta #320
• Add FromMeta impl for syn::ExprRange #329

v0.20.10 (July 9, 2024)

• Add #[allow(clippy::manual_unwrap_or_default)] to all generated impls to avoid causing clippy fails in crates using darling #296
• Properly initialize attrs magic field in derived FromAttributes impls #297

v0.20.9 (May 15, 2024)

• Allow word-form for newtype enum variants whose only field produces a value when from_none is called on their type #249
• Add FromMeta impls for the std::num::NonZero* types #288
• Fix panic in number FromMeta impls when the parsed value is too large for the receiver type #289

v0.20.8 (February 23, 2024)

• Add #[darling(with = ...)] support to attrs magic field to allow using custom receiver types for attrs #273

v0.20.7 (February 22, 2024)

• Add #[darling(flatten)] to allow forwarding unknown fields to another struct #146
• Don't suggest names of skipped fields in derived impls #268

v0.20.6 (February 14, 2024)

• Fix some missing syn invisible group handling in FromMeta impls #263
• Fix misleading error message on Error::unexpected_type so it no longer implies the type was a literal #264
• Impl FromMeta Vec of literals, e.g. LitStr #265

v0.20.5 (January 30, 2024)

• Add Flag::span inherent method, as Flag can no longer impl syn::spanned::Spanned #242

... (truncated)

Commits

• 3c17242 Bump version to 0.21.0
• cd5da98 Update CHANGELOG
• a3f7bb1 impl from_list for () (#354)
• 37ddb05 Update changelog
• 9762245 Impl UsesTypeParams and UsesLifetimes for WithOriginal
• ec867c2 Trying again to avoid duplicate CI tasks
• 15be7b3 NFC: Replace some syn paths with use
• 366d53d Avoid duplicate CI runs on pushes that become PRs
• 09f6219 Add test for flatten behavior with multiple errors
• aff17ba Add syn::parse::Parse support for FromMeta derive macro (#350)
• Additional commits viewable in compare view

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[jsdanielh]

@dependabot rebase

[jsdanielh]

@dependabot rebase