Update .travis.yml

Author: thinkingserious

.travis.yml

@@ -7,7 +7,7 @@ install:
 - nuget restore CSharpHTTPClient/CSharpHTTPClient.sln
 - nuget install NUnit.Runners -Version 2.6.4 -OutputDirectory testrunner
 script:
-- xbuild /p:Configuration=BuildNet45 CSharpHTTPClient/CSharpHTTPClient.sln
+- xbuild /p:Configuration=Release CSharpHTTPClient/CSharpHTTPClient.sln
 - mono ./testrunner/NUnit.Runners.2.6.4/tools/nunit-console.exe UnitTest/bin/Release/UnitTest.dll
 notifications:
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