Bump rustler from 0.27.0 to 0.28.0 in /native/html5ever_nif (#88)

Bumps [rustler](https://github.com/rusterlium/rustler) from 0.27.0 to 0.28.0.
- [Release notes](https://github.com/rusterlium/rustler/releases)
- [Changelog](https://github.com/rusterlium/rustler/blob/master/CHANGELOG.md)
- [Commits](rusterlium/rustler@rustler-0.27.0...rustler-0.28.0)

---
updated-dependencies:
- dependency-name: rustler
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

native/html5ever_nif/Cargo.toml

@@ -10,7 +10,7 @@ path = "src/lib.rs"
 crate-type = ["cdylib"]
 
 [dependencies]
-rustler = "0.27.0"
+rustler = "0.28.0"
 
 html5ever = "0.26"
 markup5ever = "0.11"