changelog updated for release 0.2.5

[Shekharrajak]

Fixes:

• Fixed Rubocop offenses coming from version 0.60 #125 (by @Shekharrajak)
• Updated README.md and Contribution Guide #129, #131, #133,

  139, #141 (by @Shekharrajak)

• Removed the duplicate highcharts.css #145 (by @snpd25)
• [Majaor Fix] Windows installation error fix #147 (by @kojix2 & @Shekharrajak)

[coveralls]

Pull Request Test Coverage Report for Build 798

• 0 of 0 changed or added relevant lines in 0 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage decreased (-0.01%) to 98.109%

---

Totals
Change from base Build 793:	-0.01%
Covered Lines:	3164
Relevant Lines:	3225

---

💛 - Coveralls