Rename target_entity to target_dataframe_name

[thehomebrewnerd]

Closes #241

Renames target_entity to target_dataframe_name to be consistent with Featuretools terminology.

[codecov]

Codecov Report

Merging #276 (84b30de) into main (7f2e039) will not change coverage.
The diff coverage is 100.00%.

@@           Coverage Diff           @@
##             main     #276   +/-   ##
=======================================
  Coverage   99.92%   99.92%           
=======================================
  Files          28       28           
  Lines        1324     1324           
=======================================
  Hits         1323     1323           
  Misses          1        1           

Impacted Files	Coverage Δ
composeml/conftest.py	100.00% <ø> (ø)
composeml/tests/test_featuretools.py	100.00% <ø> (ø)
composeml/tests/test_label_maker.py	100.00% <ø> (ø)
composeml/tests/test_label_serialization.py	100.00% <ø> (ø)
composeml/tests/test_label_times.py	100.00% <ø> (ø)
composeml/label_maker.py	100.00% <100.00%> (ø)
composeml/label_times/description.py	100.00% <100.00%> (ø)
composeml/label_times/object.py	100.00% <100.00%> (ø)
composeml/tests/test_data_slice/test_extension.py	100.00% <100.00%> (ø)
...mposeml/tests/test_label_transforms/test_sample.py	100.00% <100.00%> (ø)

[jeff-hernandez]

LGTM