add hero template engine

[shiyanhui]

Please check if what you want to add to awesome-go list meets quality standards before sending pull request. Thanks!

Please provide package links to:

• github.com repo: https://github.com/shiyanhui/hero
• godoc.org: https://godoc.org/github.com/shiyanhui/hero
• goreportcard.com: https://goreportcard.com/report/github.com/shiyanhui/hero
• coverage service link (gocover, coveralls etc.): https://gocover.io/github.com/shiyanhui/hero

Note: that new categories can be added only when there are 3 packages or more.

Make sure that you've checked the boxes below before you submit PR:

• I have added my package in alphabetical order
• I know that this package was not listed before
• I have added godoc link to the repo and to my pull request
• I have added coverage service link to the repo and to my pull request
• I have added goreportcard link to the repo and to my pull request
• I have read Contribution guidelines and Quality standard.

Thanks for your PR, you're awesome! 👍