fix(core): Allow to use '_' and '.' in bucket name

[topstone]

Description

Updating a bucket is always failed when bucket name contains '_' or '.'.

(Scoop v0.2.0 - Released at 2022-05-10)

Motivation and Context (How to reproduce the error)

> scoop bucket add aaa_bbb SOME-REPO-URL
Checking repo... OK
The aaa_bbb bucket was added successfully.
> scoop update SOME-MANIFEST-IN-REPO-AAA_BBB
Couldn't find manifest for 'aaa_bbb'.

How Has This Been Tested?

Sorry for no tests, no docs. I'm not good at PowerShell, just found out where to fix.

Checklist:

• I have read the Contributing Guide.
• I have ensured that I am targeting the develop branch.
• I have updated the documentation accordingly.
• I have updated the tests accordingly.
• I have added an entry in the CHANGELOG.

[niheaven]

Please update the changelog

[topstone]

Updated 'CHANGELOG.md'. Please review it.