Update dependency org.apache.poi:poi to v4

[dev-mend-for-github-com]

This PR contains the following updates:

Package	Type	Update	Change
org.apache.poi:poi	compile	major	3.8 → 4.1.1

By merging this PR, the issue #3 will be automatically resolved and closed:

Severity	CVSS Score	Vulnerability	Reachability
High	7.5	CVE-2017-12626
Medium	5.5	CVE-2017-5644
Medium	5.5	CVE-2019-12415
Medium	5.3	CVE-2012-0213
Medium	5.3	CVE-2014-9527
Medium	4.8	WS-2016-7061
Low	3.7	CVE-2014-3529
Low	3.7	CVE-2014-3574

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