Replace Property depends_on with observe

[aaronayres35]

Note these changes now make apptools require traits >= 6.2. I checked to specify this requirement, but it appears as though traits isn't even explicitly listed as a requirement, but rather is implicitly required through traitsui (which now explicitly requires traits >= 6.2). EDIT: I've added traits>=6.2.0 as an explicit required dependency on this PR.

apptools/setup.py

Lines 305 to 308 in 96c3af4

	install_requires=[
	'configobj',
	'traitsui',
	],

Checklist

• Add a news fragment if this PR is news-worthy for end users. (see docs/releases/README.rst)

[rahulporuri]

LGTM

[aaronayres35]

Agh, I forgot a news fragment. I will open a separate PR.

[rahulporuri]

@aaronayres35 dunno if this is worth a news fragment - well maybe a news fragment mentioning that we now explicitly depend on traits >= 6.2.0.

[aaronayres35]

@aaronayres35 dunno if this is worth a news fragment - well maybe a news fragment mentioning that we now explicitly depend on traits >= 6.2.0.

I guess that is true, we have had changelog entries for otc-> observe changes in other packages, but they typically contain a list of all PRs involved, eg depends_on, dynamic and static handlers, _name_changed, etc. I guess I will just close #290 .