msbuild parser does not recognize linker warnings

The msbuild parser already recognizes linker errors but not warnings (see JENKINS-3582).

LINK : fatal error LNK1181: cannot open input file 'TestLib.lib'

is correctly detected (see regression test in MsBuildParserTest.java). Warnings like 

LINK : warning LNK4217: symbol 'XYZ' defined in 'abc.obj' is imported by 'def.obj' in function 'FGH'
LINK : warning LNK4286: symbol 'XYZ' defined in 'abc.obj' is imported by 'def.obj'

 are not recognized. The issues seems to be in the regexp

(.*)\\s*:.*error\\s*(LNK[0-9]+):\\s*(.*)

in file https://github.com/jenkinsci/analysis-model/blob/master/src/main/java/edu/hm/hafner/analysis/parser/MsBuildParser.java#L27 that only detects errors not warnings.