Fall-back for wrongly formatted content-disposition headers

[Aeon512]

Some servers provided wrongly formatted content-disposition headers, e.g. Artifactory writes as Content-Disposition

attachment; filename="setup.exe"; filename*=UTF-8''"setup.exe"

where the quotations (") within the filename* parameter yield a C# Format-Exception and cause a error message to be displayed. Since AutoUpdater.NET does not rely on the Content-Disposition Header but can fall-back to the filename from the download URL, this PR catches such errors and ignores such faulty Content-Disposition headers.

[Aeon512]

Thanks for accepting.
@ravibpatel Any plans for an 1.7.8 or 1.8.0 version? :-)
Seems like there is just the git tag missing....