tests/fix: Create `AuthenticateData` fuzz-target and fix missing `\r\n`.

[coveralls]

Pull Request Test Coverage Report for Build 5266542734

• 0 of 2 (0.0%) changed or added relevant lines in 1 file are covered.
• 1 unchanged line in 1 file lost coverage.
• Overall coverage decreased (-0.01%) to 92.584%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
src/codec/encode.rs	0	2	0.0%
<!--	Total:	0	2	0.0%	-->

Files with Coverage Reduction	New Missed Lines	%
src/codec/encode.rs	1	89.76%
<!--	Total:	1		-->

Totals
Change from base Build 5254494199:	-0.01%
Covered Lines:	9064
Relevant Lines:	9790

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💛 - Coveralls