mention removal of examples/ in distribution

CHANGELOG.md

@@ -2,5 +2,6 @@
 
 -  v1.5.0: Last release supporting Python 2.
    - Added an environment variable `PANDOCFILTER_CLEANUP` that when `get_filename4code` is used, temporary directory will be cleaned up automatically. See #88.
+   - `examples/` is no longer included in the distribution (i.e. source distribution or binary wheels found on PyPI.) This should be a backward incompatible change as `examples/` is never exposed as a Python module, nor entry points.
    - Added a couple of examples.
    - See more in <https://github.com/jgm/pandocfilters/compare/1.4.3...1.5.0>.