community/py3-entrypoints: upgrade to 0.4

0.3...0.4

1ae40200 Add note about multiple dist-info folders
61fdce75 Test against Python 3.7
8f2575ee Use set comprehension
8d75e986 Fix link to entry_points
9ee2991c Added a sample folder of a editable installation (pip install -e)
bd8d41a3 Treat editable installs as Distributions too
60ff8506 Added a test for iter_files_distros with editable installs
9a05b6e0 Document motvation / constrast to pkg_resources.
edb7d2ef Revise explanation to address misconception.
8ddc1e1e Use list multiplication to duplicate entry
1869c484 Switch build-backend to flit_core
715207ad Constrain version of flit_core used for build
b291f36e Add Github actions workflow to run tests
d2d7c009 Remove Travis CI config
be2d41da Fix Python 3.10 in YAML
1819b2f2 use glob.escape() on the folder to allow paths with brackets []
86dce055 Bump minimum supported Python to 3.6
f658511e Point to importlib.metadata in README
ebdf2d8e Version number -> 0.4