Update dependency junit:junit to v4.13.1

[dev-mend-for-github-com[bot]]

This PR contains the following updates:

Package	Type	Update	Change
junit:junit (source)	compile	minor	4.8.2 -> 4.13.1
junit:junit (source)	test	minor	4.8.2 -> 4.13.1

By merging this PR, the issue #9 will be automatically resolved and closed:

Severity	CVSS Score	CVE	Reachability
Medium	4.4	CVE-2020-15250	Unreachable

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