avm2: Replace `json` with `serde_json`

The `json` crate seems unmaintained, and recently also causes compile
errors with stable Rust 1.59.0. On the other hand, `serde_json` is
very maintained and more popular.

However, from some reason a cyclic package dependency has introduced
by this change. For now use a workaround from: tkaitchuck/aHash#95 (comment)

xml: Silently fail in `disown_parent`

Instead of returning a `Result` which is anyway always handled with
a `log::warn!()`, simply `log::warn!()` in place of error.

chore: Re-generate `Cargo.lock`

`Cargo.lock` seems to got broken by ruffle-rs#6265.
Fix it using `cargo generate-lockfile`.

build(deps): bump clap from 3.0.14 to 3.1.1

Bumps [clap](https://github.com/clap-rs/clap) from 3.0.14 to 3.1.1.
- [Release notes](https://github.com/clap-rs/clap/releases)
- [Changelog](https://github.com/clap-rs/clap/blob/master/CHANGELOG.md)
- [Commits](clap-rs/clap@v3.0.14...v3.1.1)

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

Signed-off-by: dependabot[bot] <[email protected]>

web: Remove tests on Node.js 14

There seems to be no good reason for testing on Node.js other than
the current LTS. Moreover, npm@6 has a wontfix issue when upgrading
to 8.4 on Windows, which requires a complex workaround: npm/cli#4341 (comment).

So avoid it by simply not supporting it.

ci: Migrate to Windows Server 2022

Per actions/runner-images#4856,
`windows-latest` will default to `windows-2022` soon (not later than
March, 6). Since it seems like we still run on `windows-2019`, force the
migration by specifying `windows-2022` explicitly.

Since actions/runner-images#5050 is
merged, this should fix the failing Web tests on mismatched Chrome and
chromedriver versions.

TODO: Once `windows-latest` defaults to `windows-2022` (again, March, 6),
change back to `windows-latest`.

build(deps): bump rand from 0.8.4 to 0.8.5

Bumps [rand](https://github.com/rust-random/rand) from 0.8.4 to 0.8.5.
- [Release notes](https://github.com/rust-random/rand/releases)
- [Changelog](https://github.com/rust-random/rand/blob/master/CHANGELOG.md)
- [Commits](rust-random/rand@0.8.4...0.8.5)

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

Signed-off-by: dependabot[bot] <[email protected]>

build(deps): bump futures from 0.3.19 to 0.3.21

Bumps [futures](https://github.com/rust-lang/futures-rs) from 0.3.19 to 0.3.21.
- [Release notes](https://github.com/rust-lang/futures-rs/releases)
- [Changelog](https://github.com/rust-lang/futures-rs/blob/master/CHANGELOG.md)
- [Commits](rust-lang/futures-rs@0.3.19...0.3.21)

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

Signed-off-by: dependabot[bot] <[email protected]>

avm2: Fix invalid option

avm1: Merge `XmlDocument` into `XmlObject`

As `XmlDocument` and `XmlObject` had 1-to-1 relation, and `XmlDocument`
is already tightly coupled with AVM1, there's no good reason for them
being separate objects.

This brings us one step closer towards an XML implementation hosted
completely in AVM1.

A future PR will merge `XmlNode` into `XmlNodeObject` in a similar
manner.