1.2.1 is, as of this commit, the most recent version of the gadget.
The version currently used, 1.0.0b12 is not compatible with Python 3.9:
the build errors out on missing arguments for _PyEval_EvalFrameDefault.
Python 3.9 is the version of Python that will be shipped with the
upcoming debian release.
Support for 3.9 was merged in before the final 1.0.0 version. So,
upgrading the gadget will bring in python 3.9 support
Change Dockerfile to install lua, luajit and love and also to install
nodejs 12 needed to build the lua debug adapter. Create the
love-headless test in support/test/lua to test love without an x server.
This adds a --upgrade option to install_gadget.py and makes
VimspectorUpdate only update things which have changed.
To do this, we record the gadget spec in a manfiest file and compare it
with the current spec when in upgrade mode.
'Changed' in this case means that the gadget spec has changed from the
last time the installer was run. It does _not_ actually check the
presence of the gadget.
