Update dependency xmlschema to v2.2.2

[renovate]

This PR contains the following updates:

Package	Change	Age	Adoption	Passing	Confidence
xmlschema	==2.2.1 -> ==2.2.2

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Release Notes

sissaschool/xmlschema

v2.2.2

Compare Source

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• Fix mixed content extension with empty content (issue #​337)
• Fix lru_cache() usage on global maps caching

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[codecov]

Codecov Report

Merging #236 (d446d3e) into master (bc6d357) will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master     #236   +/-   ##
=======================================
  Coverage   99.63%   99.63%           
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  Files           4        4           
  Lines         274      274           
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  Hits          273      273           
  Misses          1        1