provide whatsnew file

1 job for latest-1.2 in 1 minute and 51 seconds (queued for 2 seconds)
Status Name Job ID Coverage
failed job #15246


Name Stage Failure
job Test There is an unknown failure, please try again
  "Performance can be very poor in this case.", RuntimeWarning)
python3 -c 'import sys, sphinx; sys.exit(sphinx.main(sys.argv))' -b html -d build/doctrees source build/html
Traceback (most recent call last):
File "<string>", line 1, in <module>
ImportError: No module named 'sphinx'
make: *** [html] Error 1
Makefile:65: recipe for target 'html' failed
make: Leaving directory '/builds/kwant/kwant/doc'
ERROR: Build failed: exit code 1