BLD: add xlwt py3 version to build matrix

[jreback]

apparently we are using the regular xlwt on the 3.3 build, which doesn't (it skips everything), so need

still in dev on xlwt master branch

[jreback]

python-excel/xlwt#32

[jreback]

cc @jmcnamara

is this correct?

[jmcnamara]

@jreback
That is correct. Currently xlwt doesn't support Python 3. However, xlrd, OpenPyXL and XlsxWriter do (i,e., all the other Excel modules that Pandas uses).

Note, the xlwt-future PR has been there for a while and looks unlikely to be accepted without a lot of rework.

You could also drop xlwt support from the Pandas 3.x dependencies until it is Py3 compatible.