Occasionally when the `isolated` tests run in CI, this error is seen:
```
inspec-reporter-html2::when run on a basic profile#test_0002_should produce valid HTML:
Errno::ENOENT: No such file or directory @ apply2files - /tmp/temp20200625-1802-2izu7e.html
/usr/local/lib/ruby/2.6.0/fileutils.rb:1437:in `unlink'
/usr/local/lib/ruby/2.6.0/fileutils.rb:1437:in `block in remove_file'
/usr/local/lib/ruby/2.6.0/fileutils.rb:1442:in `platform_support'
/usr/local/lib/ruby/2.6.0/fileutils.rb:1436:in `remove_file'
/usr/local/lib/ruby/2.6.0/fileutils.rb:775:in `remove_file'
/usr/local/lib/ruby/2.6.0/fileutils.rb:562:in `block in rm'
/usr/local/lib/ruby/2.6.0/fileutils.rb:561:in `each'
/usr/local/lib/ruby/2.6.0/fileutils.rb:561:in `rm'
lib/plugins/inspec-reporter-html2/test/functional/inspec_reporter_html2_test.rb:9:in `teardown'
```
It should be OK to ignore the failure to delete the test file - the issue doesn't reproduce on laptops, and CI uses clean VMs each time.
Signed-off-by: James Stocks <jstocks@chef.io>
This uses html-proofer, which adds in nokogiri as a testing dep.
I expect we'll be using nokogiri soon anyway for the JUnit reporter.
Signed-off-by: Clinton Wolfe <clintoncwolfe@gmail.com>