gemspec: Fix version syntax.

2.0.0 Codename Random (estebanz01#12)

* statistical-test: Chi-Squared Goodness of fit. (estebanz01#11)
* statistical-test: Paired T-tests. (estebanz01#14)
* Wilcoxon Rank-sum test / Mann-Whitney U test (estebanz01#15)
* Generate gaussian random numbers (estebanz01#16)
* distribution: normal: Generate random gaussian samples.
* distribution: Weibull: Random sample that follows Weibull distribution.

* distribution: Student's T: Generate random samples for T distribution.

NOTE: The random sampling process is generation random values that
are similar to an uniform random sample. Not sure why.

* version 2.0.0! 🎉

version: Update version.

version: 1.0.1 - Fixed issue with loading.

Update version.rb

Bump to version 1.0.0

gemspec: Rename gem due to name collition.