Update usvg requirement from 0.20 to 0.21

[dependabot]

Updates the requirements on usvg to permit the latest version.

Release notes

Sourced from usvg's releases.

v0.21.0

• viewsvg is a simple application that showcases resvg capabilities
• resvg-0.*.0.tar.xz is a sources archive with vendored Rust dependencies
• resvg-explorer-extension.exe is an SVG thumbnailer for Windows Explorer

Changelog

Sourced from usvg's changelog.

[0.21.0] - 2022-02-13

Added

• usvg::ImageHrefResolver that allows a custom xlink:href handling. Thanks to antmelnyk.
• usvg::Options::image_href_resolver
• Support for GIF images inside the <image> element.
• (fontdb) Support for loading user fonts on Windows.
• (fontdb) Support for parsing fontconfig config files on Linux. For now, only to retrieve a list of font dirs.

Changed

• MSRV bumped to 1.51
• usvg::ImageKind stores data as Arc<Vec<u8>> and not just Vec<u8> now.

Fixed

• Every nested svg element defines a new viewBox now. Previously, we were always using the root one.
• Correctly handle SVG size calculation when SVG doesn't have a size and any elements.
• Improve groups ungrouping speed.

[0.20.0] - 2021-12-29

Changed

• resvg::render and resvg::render_node accept a transform now.
• (c-api) resvg_render and resvg_render_node accept a transform now.
• usvg::Color is a custom type and not a svgtypes::Color reexport now.
• usvg::Color doesn't contain alpha anymore, which have been added in v0.16 Alpha would be automatically flattened. This makes Micro SVG compatible with SVG 1.1 again.
• (c-api) Rename RESVG_FIT_TO_* into RESVG_FIT_TO_TYPE_*.

Fixed

• The --background argument in resvg correctly handles alpha now.
• Fix building usvg without filter feature but with export.

[0.19.0] - 2021-10-04

Added

• Better text-on-path converter accuracy by accounting the current transform.

Changed

• usvg::NodeExt::abs_transform includes current node transform now.
• Improved turbulence filter performance. Thanks to akindle.
• Multiple dependencies updated.

[0.18.0] - 2021-09-12

Added

• filter build feature. Enabled by default.
• usvg::PathBbox and resvg_path_bbox (to C API).

Changed

• (usvg) All filter related types are under the filter module now.

... (truncated)

Commits

• b923587 Version bump.
• 455e693 Use platform independent decoding feature for JPEG.
• 3a2cc6a Bump MSRV.
• 6805d57 Update dependencies.
• 8282b84 Every nested svg element defines a new viewBox now.
• e80f593 Improve groups ungrouping speed.
• 5998e9b Correctly handle SVG size calculation when SVG doesn't have a size and any el...
• 422bee6 Update fontdb.
• 87b1def Add gif images support.
• e3cd65d Simple refactoring.
• Additional commits viewable in compare view

Dependabot will resolve any conflicts with this PR as long as you don't alter it yourself. You can also trigger a rebase manually by commenting @dependabot rebase.

---

Dependabot commands and options

You can trigger Dependabot actions by commenting on this PR:

• @dependabot rebase will rebase this PR
• @dependabot recreate will recreate this PR, overwriting any edits that have been made to it
• @dependabot merge will merge this PR after your CI passes on it
• @dependabot squash and merge will squash and merge this PR after your CI passes on it
• @dependabot cancel merge will cancel a previously requested merge and block automerging
• @dependabot reopen will reopen this PR if it is closed
• @dependabot close will close this PR and stop Dependabot recreating it. You can achieve the same result by closing it manually
• @dependabot ignore this major version will close this PR and stop Dependabot creating any more for this major version (unless you reopen the PR or upgrade to it yourself)
• @dependabot ignore this minor version will close this PR and stop Dependabot creating any more for this minor version (unless you reopen the PR or upgrade to it yourself)
• @dependabot ignore this dependency will close this PR and stop Dependabot creating any more for this dependency (unless you reopen the PR or upgrade to it yourself)

[dependabot]

Superseded by #12.