Closes #10 add function `create_iso8601()` #60

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Render README	0s
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Check / (4.1)	1m 16s
Check / (4.2)	1m 31s
Code Coverage / Test Coverage	1m 48s
Check / (4.3)	1m 27s
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Check / (devel)	1m 45s
Code Style / Code Style	1m 19s
Lint / Lint	1m 30s
Man Pages / Roxygen	1m 43s
Code Coverage / Generate badge for coverage	5s
	12m 28s

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