test requirements: Update beautifulsoup4 to 4.5.0

* Beautiful Soup is no longer compatible with Python 2.6. This
  actually happened a few releases ago, but it's now official.

* Beautiful Soup will now work with versions of html5lib greater than
  0.99999999.

* If a search against each individual value of a multi-valued
  attribute fails, the search will be run one final time against the
  complete attribute value considered as a single string. That is, if
  a tag has class="foo bar" and neither "foo" nor "bar" matches, but
  "foo bar" does, the tag is now considered a match.

  This happened in previous versions, but only when the value being
  searched for was a string. Now it also works when that value is
  a regular expression, a list of strings, etc.

* Fixed a bug that deranged the tree when a whitespace element was
  reparented into a tag that contained an identical whitespace
  element.

* Added support for CSS selector values that contain quoted spaces,
  such as tag[style="display: foo"].

* Corrected handling of XML processing instructions.

* Corrected an encoding error that happened when a BeautifulSoup
  object was copied.

* The contents of <textarea> tags will no longer be modified when the
  tree is prettified.

* When a BeautifulSoup object is pickled but its tree builder cannot
  be pickled, its .builder attribute is set to None instead of being
  destroyed. This avoids a performance problem once the object is
  unpickled.

* Specify the file and line number when warning about a
  BeautifulSoup object being instantiated without a parser being
  specified.

* The `limit` argument to `select()` now works correctly, though it's
  not implemented very efficiently.

* Fixed a Python 3 ByteWarning when a URL was passed in as though it
  were markup. Thanks to James Salter for a patch and
  test.

* We don't run the check for a filename passed in as markup if the
  'filename' contains a less-than character; the less-than character
  indicates it's most likely a very small document.

misc/requirements/requirements-tests.txt

@@ -1,6 +1,6 @@
 # This file is automatically generated by scripts/dev/recompile_requirements.py
 
-beautifulsoup4==4.4.1
+beautifulsoup4==4.5.0
 CherryPy==6.2.0
 coverage==4.1
 decorator==4.0.10