chore(deps): update base64 requirement from 0.13 to 0.21 in /ucan

[dependabot]

Updates the requirements on base64 to permit the latest version.

Changelog

Sourced from base64's changelog.

0.21.0

(not yet released)

Migration

Functions

< 0.20 function	0.21 equivalent
encode()	engine::general_purpose::STANDARD.encode() or prelude::BASE64_STANDARD.encode()
encode_config()	engine.encode()
encode_config_buf()	engine.encode_string()
encode_config_slice()	engine.encode_slice()
decode()	engine::general_purpose::STANDARD.decode() or prelude::BASE64_STANDARD.decode()
decode_config()	engine.decode()
decode_config_buf()	engine.decode_vec()
decode_config_slice()	engine.decode_slice()

The short-lived 0.20 functions were the 0.13 functions with config replaced with engine.

Padding

If applicable, use the preset engines engine::STANDARD, engine::STANDARD_NO_PAD, engine::URL_SAFE, or engine::URL_SAFE_NO_PAD. The NO_PAD ones require that padding is absent when decoding, and the others require that canonical padding is present .

If you need the < 0.20 behavior that did not care about padding, or want to recreate < 0.20.0's predefined Configs precisely, see the following table.

0.13.1 Config	0.20.0+ alphabet	encode_padding	decode_padding_mode
STANDARD	STANDARD	true	Indifferent
STANDARD_NO_PAD	STANDARD	false	Indifferent
URL_SAFE	URL_SAFE	true	Indifferent
URL_SAFE_NO_PAD	URL_SAFE	false	Indifferent

0.21.0-rc.1

• Restore the ability to decode into a slice of precisely the correct length with Engine.decode_slice_unchecked.
• Add Engine as a pub use in prelude.

0.21.0-beta.2

Breaking changes

• Re-exports of preconfigured engines in engine are removed in favor of base64::prelude::... that are better suited to those who wish to use the entire path to a name.

... (truncated)

Commits

• d7fb31c v0.21.0
• 8350376 Merge pull request #207 from marshallpierce/mp/api-rework
• 726f784 v0.21.0-rc.1
• b29ab01 Add Engine in prelude
• 64bbcc0 Remove no longer needed test helpers
• 0f981bd Add decode_slice_unchecked to restore ability to decode into a precisely size...
• a51e822 v0.21.0-beta.2
• 936569a Move re-exports from engine to prelude
• 53e1091 Fix release notes typo
• b03eb5a v0.21.0-beta.1
• Additional commits viewable in compare view

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