bug(#282): Fixed StrictXML toString()

See #284, release log:

• b37b7b1 by @yegor256: Merge pull request #284 from m...
• dd57a92 by @maxonfjvipon: bug(#282): Fixed StrictXML toS...
• 78f4b79 by @maxonfjvipon: bug(#282): Made StrictXML lazy
• 392045f by @renovate[bot]: chore(deps): update dependency...
• 87ad029 by @renovate[bot]: chore(deps): update junit5 mon...
• 08b50ad by @yegor256: extra test

Released by Rultor 2.0-SNAPSHOT, see build log