Generated changelog conflict with Prettier opinions

[jelhan]

The changelog generated by lerna-changelog does not follow Prettier's opinions for markdown files. It especially conflicts in two aspects:

1. Missing blank line between headline and list
2. Using asterisk (*) for the list item instead of dash (-)

The mismatch is problematic for projects checking in CI that all files, including CHANGELOG.md, are formatted with Prettier.

Generated by lerna-changelog:

#### :bug: Bug Fix
* [#1](https://examples.com) foo ([@jelhan](https://github.com/jelhan))

Expected by Prettier

#### :bug: Bug Fix

- [#1](https://examples.com) foo ([@jelhan](https://github.com/jelhan))

See this example in Prettier playground: https://prettier.io/playground/#N4Igxg9gdgLgprEAuEBidqAESBGBXAcyUwCFDMAxASwA8AdKAKkwG1UBGAXQAoALGGAAcAzkgD0YuDQCGAW0EAbOMIB0kWQEpMAMwgRM3FgAEAVnAW9pUHvyGiJBKjF54caiLLFmLVjRpAANCAQgjBU0MLIoNIATjEQAO4ACrEIkSjSCgnSAJ6RQTgx0mAA1nAwAMpycAAyVFBwyNqZwnAFRaXlFYLF9QTIMDF4bSCtslQDQyNSgnAxVLIIMJkAKnNQsVTKTS0jwn1KAIp4EPA7Cq1BJsI0FQdwx6eNSM0XIwCOJ-BJ8SLIINJhABaBpwAAm4MCIEG0ioCj6AGEPLJpP9MgoofsoAQlABBATzfDfOZ1BrnS4gfiyBQAdV4TmUPTAcAqaScVAAbk4cv8wMJ8iAOcMAJJQCGwCpgeahXFiiowHJKckjQTxVo0oqCf6q5RzDmNIL1VoxGA-aQEFHKoI9GLG-4omIlMGJKBQ1X1GA0qhg5zIAAcAAYgjE4J8qCGzRbUS9dkFljgvT7eMgAExBPCtFbSHDpV4UuCyHDgiFgmpWAh4c1wCgQGIogR9NF4GAQEAAXzbQA