composer: update lightools/xml requirement from ^2.0|^3.0 to ^4.0.0

[dependabot]

Updates the requirements on lightools/xml to permit the latest version.

Release notes

Sourced from lightools/xml's releases.

v4.0.0

Breaking changes:

• PHP 8.4+ is now required (#36)
• New DOM API: XmlLoader::loadXml() now returns Dom\XMLDocument and XmlLoader::loadHtml() returns Dom\HTMLDocument, previously both returned DOMDocument (#36)
• HTML5 parser: loadHtml() now uses the spec-compliant HTML5 parser of Dom\HTMLDocument, the parse tree can differ from the legacy libxml2 parser for malformed markup (#36)

Migration:

• Replace DOMDocument type-hints of loader results with Dom\XMLDocument / Dom\HTMLDocument
• Check your DOM traversal code against the new DOM API, some legacy methods behave differently or are not available
• Verify HTML parsing of malformed markup, the HTML5 parser can produce a different tree

Improvements:

• XmlException::__construct() now accepts a $previous throwable (#36)
• Tests migrated from nette/tester to PHPUnit (#37)

Commits

• See full diff 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 show <dependency name> ignore conditions will show all of the ignore conditions of the specified dependency
• @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)