Put semver.org link between parenthesis

[avivace]

The help text for the version string is currently a bit strange to read:

Mostly relevant for software and dataset uploads. A semantic version string is preferred see [semver.org](https://semver.org/), but any version string is accepted.

This PR just puts the semver.org link between parenthesis so it's easier to follow the sense of the phrase.

[avivace]

Suggested change

	) but any version string is accepted.
	) but any string is accepted.

Also, I suggest to remove "version string" to just use "string" here, because it better suggests that any string can be used as a version (while "version string" may suggest x.y.z). E.g. revision-conference-80 is accepted in this field, as well as

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without triggering any validation error