cla: Add @bkmgit to `.clabot`.

[duesee]

Urgs... thanks 🙈

[coveralls]

Pull Request Test Coverage Report for Build 3949431998

• 0 of 0 changed or added relevant lines in 0 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage remained the same at 53.588%

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Totals
Change from base Build 3929458399:	0.0%
Covered Lines:	30653
Relevant Lines:	57201

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💛 - Coveralls

[duesee]

I remember this already happened once :-) (I reformatted the .clabot file so that it is not so easy anymore to overlook the first line.)