chore(deps): bump swc_ecma_ast from 0.90.16 to 0.90.20 in /backend (#561)

Bumps [swc_ecma_ast](https://github.com/swc-project/swc) from 0.90.16 to 0.90.20.
- [Release notes](https://github.com/swc-project/swc/releases)
- [Changelog](https://github.com/swc-project/swc/blob/main/CHANGELOG.md)
- [Commits](https://github.com/swc-project/swc/commits)

---
updated-dependencies:
- dependency-name: swc_ecma_ast
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

backend/Cargo.lock

@@ -3460,9 +3460,9 @@ dependencies = [
 
 [[package]]
 name = "swc_ecma_ast"
-version = "0.90.16"
+version = "0.90.20"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "cbe26d2bc1a5b795b231a483bb8d070329bc8ba865d28dfa566cb1cf96e5d560"
+checksum = "f712949db06518bec7b7e050aa3bcde749a74fbf79f4f520ab179d0445b63593"
 dependencies = [
  "bitflags",
  "is-macro",