Make it possible to manually trigger cron job

[rahulporuri]

This PR makes it possible to manually trigger the cron job - using workflow_dispatch. Ref enthought/ets#68

[rahulporuri]

the "macos-latest" + "pyqt5" job segfaulted

test_force_exit (pyface.tests.test_gui_application.TestGUIApplication) ... Traceback (most recent call last):
  File "/Users/runner/work/pyface/pyface/.edm/envs/pyface-test-3.6-pyqt5/lib/python3.6/site-packages/pyface/ui/qt4/gui.py", line 194, in _dispatch
    self._callable(*self._args, **self._kw)
  File "/Users/runner/work/pyface/pyface/.edm/envs/pyface-test-3.6-pyqt5/lib/python3.6/site-packages/pyface/application.py", line 220, in exit
    self._exit()
  File "/Users/runner/work/pyface/pyface/.edm/envs/pyface-test-3.6-pyqt5/lib/python3.6/site-packages/pyface/gui_application.py", line 236, in _exit
    self.gui.stop_event_loop()
AttributeError: '_Undefined' object has no attribute 'stop_event_loop'
Fatal Python error: Aborted

Current thread 0x0000000110b42dc0 (most recent call first):
  File "/Users/runner/work/pyface/pyface/.edm/envs/pyface-test-3.6-pyqt5/lib/python3.6/site-packages/pyface/ui/qt4/widget.py", line 61 in show
  File "/Users/runner/work/pyface/pyface/.edm/envs/pyface-test-3.6-pyqt5/lib/python3.6/site-packages/pyface/i_window.py", line 233 in open
  File "/Users/runner/work/pyface/pyface/.edm/envs/pyface-test-3.6-pyqt5/lib/python3.6/site-packages/pyface/i_splash_screen.py", line 75 in open
  File "/Users/runner/work/pyface/pyface/.edm/envs/pyface-test-3.6-pyqt5/lib/python3.6/site-packages/pyface/ui/qt4/gui.py", line 55 in __init__
  File "/Users/runner/work/pyface/pyface/.edm/envs/pyface-test-3.6-pyqt5/lib/python3.6/site-packages/pyface/gui_application.py", line 169 in start
  File "/Users/runner/work/pyface/pyface/.edm/envs/pyface-test-3.6-pyqt5/lib/python3.6/site-packages/pyface/tests/test_gui_application.py", line 76 in start
  File "/Users/runner/work/pyface/pyface/.edm/envs/pyface-test-3.6-pyqt5/lib/python3.6/site-packages/pyface/application.py", line 167 in run
  File "/Users/runner/work/pyface/pyface/.edm/envs/pyface-test-3.6-pyqt5/lib/python3.6/site-packages/pyface/tests/test_gui_application.py", line 245 in test_force_exit
  File "/Users/runner/work/pyface/pyface/.edm/envs/pyface-test-3.6-pyqt5/lib/python3.6/unittest/case.py", line 605 in run
  File "/Users/runner/work/pyface/pyface/.edm/envs/pyface-test-3.6-pyqt5/lib/python3.6/unittest/case.py", line 653 in __call__
  File "/Users/runner/work/pyface/pyface/.edm/envs/pyface-test-3.6-pyqt5/lib/python3.6/unittest/suite.py", line 122 in run
  File "/Users/runner/work/pyface/pyface/.edm/envs/pyface-test-3.6-pyqt5/lib/python3.6/unittest/suite.py", line 84 in __call__
  File "/Users/runner/work/pyface/pyface/.edm/envs/pyface-test-3.6-pyqt5/lib/python3.6/unittest/suite.py", line 122 in run
  File "/Users/runner/work/pyface/pyface/.edm/envs/pyface-test-3.6-pyqt5/lib/python3.6/unittest/suite.py", line 84 in __call__
  File "/Users/runner/work/pyface/pyface/.edm/envs/pyface-test-3.6-pyqt5/lib/python3.6/unittest/suite.py", line 122 in run
  File "/Users/runner/work/pyface/pyface/.edm/envs/pyface-test-3.6-pyqt5/lib/python3.6/unittest/suite.py", line 84 in __call__
  File "/Users/runner/work/pyface/pyface/.edm/envs/pyface-test-3.6-pyqt5/lib/python3.6/unittest/suite.py", line 122 in run
  File "/Users/runner/work/pyface/pyface/.edm/envs/pyface-test-3.6-pyqt5/lib/python3.6/unittest/suite.py", line 84 in __call__
  File "/Users/runner/work/pyface/pyface/.edm/envs/pyface-test-3.6-pyqt5/lib/python3.6/unittest/runner.py", line 176 in run
  File "/Users/runner/work/pyface/pyface/.edm/envs/pyface-test-3.6-pyqt5/lib/python3.6/unittest/main.py", line 256 in runTests
  File "/Users/runner/work/pyface/pyface/.edm/envs/pyface-test-3.6-pyqt5/lib/python3.6/unittest/main.py", line 95 in __init__
  File "/Users/runner/work/pyface/pyface/.edm/envs/pyface-test-3.6-pyqt5/lib/python3.6/unittest/__main__.py", line 18 in <module>
  File "/Users/runner/work/pyface/pyface/.edm/envs/pyface-test-3.6-pyqt5/lib/python3.6/site-packages/coverage/execfile.py", line 183 in run_python_file
  File "/Users/runner/work/pyface/pyface/.edm/envs/pyface-test-3.6-pyqt5/lib/python3.6/site-packages/coverage/execfile.py", line 113 in run_python_module
  File "/Users/runner/work/pyface/pyface/.edm/envs/pyface-test-3.6-pyqt5/lib/python3.6/site-packages/coverage/cmdline.py", line 627 in do_run
  File "/Users/runner/work/pyface/pyface/.edm/envs/pyface-test-3.6-pyqt5/lib/python3.6/site-packages/coverage/cmdline.py", line 483 in command_line
  File "/Users/runner/work/pyface/pyface/.edm/envs/pyface-test-3.6-pyqt5/lib/python3.6/site-packages/coverage/cmdline.py", line 756 in main
  File "/Users/runner/work/pyface/pyface/.edm/envs/pyface-test-3.6-pyqt5/lib/python3.6/site-packages/coverage/__main__.py", line 8 in <module>
  File "/Users/runner/work/pyface/pyface/.edm/envs/pyface-test-3.6-pyqt5/lib/python3.6/runpy.py", line 85 in _run_code
  File "/Users/runner/work/pyface/pyface/.edm/envs/pyface-test-3.6-pyqt5/lib/python3.6/runpy.py", line 193 in _run_module_as_main
Command '['/Users/runner/work/pyface/pyface/.edm/envs/edm/bin/edm', 'run', '-e', 'pyface-test-3.6-pyqt5', '--', 'python', '-Xfaulthandler', '-m', 'coverage', 'run', '-p', '-m', 'unittest', 'discover', '-v', 'pyface']' returned non-zero exit status 250.

[aaronayres35]

LGTM