Update CHANGES.md for the version 0.0.5

[mrkn]

Contents that must be mentioned is below:

• [x] stairs #38 by nanobowers
• [x] block canvas #39 by nanobowers
• [x] animation example #33 by mrkn and kojix2
• [x] resolve the lineplot bug of monotonic curve rendering #37 by nanobowers
• [ ] stemplot #40 by nanobowers
• [x] color option of render method #46 by mrkn, reported by kojix2
• [ ] new documentation
  • boxplot
  • lineplot
  • stemplot
  • stairs