py-spyder: py-pyqt5 dependency also needs +webkit

[mf2k (Frank Schima)]

Something changed recently because py-spyder now needs py-pyqt5 +webengine +webkit, but the portfile only requires +webengine. Here is the runtime error I see with only that variant:

$ spyder
Traceback (most recent call last):
  File "/opt/local/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/site-packages/qtpy/QtWebEngineWidgets.py", line 22, in <module>
    from PyQt5.QtWebEngineWidgets import QWebEnginePage
ModuleNotFoundError: No module named 'PyQt5.QtWebEngineWidgets'

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/opt/local/bin/spyder", line 3, in <module>
    start.main()
  File "/opt/local/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/site-packages/spyder/app/start.py", line 193, in main
    from spyder.app import mainwindow
  File "/opt/local/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/site-packages/spyder/app/mainwindow.py", line 81, in <module>
    from qtpy import QtWebEngineWidgets  # analysis:ignore
  File "/opt/local/Library/Frameworks/Python.framework/Versions/3.7/lib/python3.7/site-packages/qtpy/QtWebEngineWidgets.py", line 26, in <module>
    from PyQt5.QtWebKitWidgets import QWebPage as QWebEnginePage
ModuleNotFoundError: No module named 'PyQt5.QtWebKitWidgets'