build: Updating mediawiki/mediawiki-codesniffer to 0.12.0
The following sniffs are failing and were disabled:
- MediaWiki.Commenting.FunctionComment.MissingDocumentationProtected
- MediaWiki.Commenting.FunctionComment.MissingDocumentationPublic
- MediaWiki.Commenting.FunctionComment.MissingParamComment
- MediaWiki.WhiteSpace.SpaceBeforeSingleLineComment.NewLineComment
The following sniffs now pass and were enabled:
- MediaWiki.Commenting.FunctionComment
- MediaWiki.WhiteSpace.SpaceBeforeSingleLineComment
Also added "composer fix" command.
Change-Id: I1bd68733db5c1fb2f81f6824ba4561a9f4f621a6