Removing reference to javaslang 2.0.0 version

[sleepytomcat]

To address #47

Here https://docs.vavr.io/#_lazy the documentation says:

Since version 2.0.0 you may also create a real lazy value (works only with interfaces):

To my understanding, this actually refers to javaslang v2.0.0, which may be confusing to vavr users. As far as I understand, any published vavr version implements this feature, so this PR proposes to remove the Since version 2.0.0 clause.

[danieldietrich]

Sorry for the slight delay ... Thank you!