Log Message:
py-dateutil: updated to 2.7.0

Version 2.7.0
- Dropped support for Python 2.6
- Dropped support for Python 3.2
- Updated zoneinfo file to 2018c
- Changed licensing scheme so all new contributions are dual licensed under
  Apache 2.0 and BSD.
- Added __all__ variable to the root package
- Added python_requires to setup.py so that pip will distribute the right
  version of dateutil.
- Added the utils submodule, for miscellaneous utilities.
- Added within_delta function to utils
- Added today function to utils
- Added default_tzinfo function to utils
- Added dedicated ISO 8601 parsing function isoparse
- Moved parser module into parser/_parser.py and officially deprecated the use
  of several private functions and classes from that module.
- Tweaked parser error message to include rejected string format
- Add support for parsing bytesarray
- Started raising a warning when the parser finds a timezone string that it
  cannot construct a tzinfo instance for (rather than succeeding with no
  indication of an error).
- Dropped the use of assert in the parser.
- Fixed to assertion logic in parser to support dates like '2015-15-May'
- Fixed IndexError in parser on dates with trailing colons
- Fixed bug where hours were not validated, leading to improper parse.
- Fixed problem parsing strings in %b-%Y-%d format.
- Fixed problem parsing strings in the %d%B%y format.
- Fixed problem parsing certain unambiguous strings when year <99
- Fixed issue with parsing an unambiguous string representation of an ambiguous
  datetime such that if possible the correct value for fold is set.
- Fixed issue with improper rounding of fractional components.
- Performance improvement to parser from removing certain min() calls.
- Significantly refactored parser code
- Implementated of __hash__ for relativedelta and weekday
- Implemented __abs__ for relativedelta.
- Fixed relativedelta.weeks property getter and setter to work for both
  negative and positive values.
- Fixed issue where passing whole number floats to the months or years
  arguments of the relativedelta constructor would lead to errors during
  addition.
- Added a pre-built tz.UTC object representing UTC
- Added a cache to tz.gettz so that by default it will return the same object
  for identical inputs. This will change the semantics of certain operations
  between datetimes constructed with tzinfo=tz.gettz(...).
- Changed the behavior of tz.tzutc to return a singleton
- Changed the behavior of tz.tzoffset to return the same object when passed the
  same inputs, with a corresponding performance improvement
- Changed the behavior of tz.tzstr to return the same object when passed the
  same inputs.
- Added .instance alternate constructors for tz.tzoffset and tz.tzstr, to
  allow the construction of a new instance if desired.
- Added the tz.gettz.nocache function to allow explicit retrieval of a new
  instance of the relevant tzinfo.
- Expand definition of tz.tzlocal equality so that the local zone is allow
  equality with tzoffset and tzutc.
- Deprecated the idiosyncratic tzstr format mentioned in several examples but
  evidently designed exclusively for dateutil, and very likely not used by
  any current users.
- Added the tz.resolve_imaginary function, which generates a real date from
  an imaginary one, if necessary.
- Fixed issue where the tz.tzstr constructor would erroneously succeed if
  passed an invalid value for tzstr.
- Fixed issue with tz.gettz for TZ variables that start with a colon.
- Added a lock to tz.tzical's cache.
- Fixed an issue with fold support on certain Python 3 implementations that
  used the pre-3.6 pure Python implementation of datetime.replace, most
  notably pypy3
- Added support for VALUE=DATE-TIME for DTSTART in rrulestr.
- Started enforcing that within VTIMEZONE, the VALUE parameter can only be
  omitted or DATE-TIME, per RFC 5545.
- Added support for TZID parameter for DTSTART in rrulestr.
- Added 'RRULE:' prefix to rrule strings generated by rrule.__str__, in
  compliance with the RFC.
- Switched to setuptools_scm for version management, automatically calculating
  a version number from the git metadata.
- Switched setup.py to use find_packages, and started testing against pip
  installed versions of dateutil in CI. Fixed issue with parser import
- Switched test suite to using pytest
- Switched CI over to use tox.
- Added a test-only dependency on freezegun.
- Reduced number of CI builds on Appveyor.
- Made xfails strict by default, so that an xpass is a failure.
- Added a documentation generation stage to tox and CI.
- Added an explicit warning when running python setup.py explaining how to run
  the test suites with pytest.
- Added requirements-dev.txt for test dependency management
- Fixed code coverage metrics to account for Windows builds
- Fixed code coverage metrics to NOT count xfails.
- Style improvement to zoneinfo.tzfile that was confusing to static type
  checkers.
- Several unused imports were removed
- Switched isinstance(*, collections.Callable) to callable, which is available
  on all supported Python versions.
- Added CONTRIBUTING.md
- Added AUTHORS.md
- Corrected setup.py metadata to reflect author vs. maintainer
- Corrected README to reflect that tests are now run in pytest.
- Updated all references to RFC 2445 (iCalendar) to point to RFC 5545.
- Corrected parse documentation to reflect proper integer offset units,
- Fixed dangling parenthesis in tzoffset documentation
- Started including the license file in wheels.
- Indendation fixes to parser docstring
- Moved many examples from the "examples" documentation into their \ 
appropriate
  module documentation pages.
- Fixed documentation so that the parser.isoparse documentation displays.
- Refactored build and release sections and added setup instructions to
  CONTRIBUTING.
- Cleaned up various dead links in the documentation.