v0.7.1: CRAN release

This release incorporates all the incredible work done by @csdaw to refactor the
various geom and position functions, fix outstanding issues, and remove
dependencies on deprecated ggplot2 functions like qplot.

It is also available on CRAN: https://cran.r-project.org/web/packages/ggbeeswarm/index.html

New features:

• Can now use new features from the beeswarm package, including compact
  swarms and 'corralling' points in overlapping groups.
• Updated examples and documentation.

Changes:

• The groupOnX argument is deprecated. ggplot2 now has logic to determine
  when a plot is 'flipped' automatically so this argument is no longer
  necessary.
• The beeswarmArgs argument is deprecated as its arguments are now called in
  geom_beeswarm directly.
• position_beeswarm is once again an exported function.
• Examples and documentation no longer use ggplot2::qplot as it has been
  hard-deprecated in ggplot2
• The license has been clarified to be GPL-3, not GPL >= 2.
• Minimum R and ggplot2 versions have changed to 3.5.0 and 3.3.0,
  respectively.

Bugfixes:

Too many to summarize here.

Acknowledgements:

A huge thank you to @csdaw, @sherrillmix, and everybody who reported and replied to issues and submitted pull requests in the last few years!