Update talks.rst

[avallbona]

Added the slides of a PyconES 2017 talk about pytest and its plugins ecosystem.

[nicoddemus]

Thanks @avallbona!

I just moved the talk to the top of the list as it is more recent. 👍

[nicoddemus]

(I'm cancelling AppVeyor)

[avallbona]

Thanks @nicoddemus !!

[blueyed]

Failure:

/home/travis/build/pytest-dev/pytest/doc/en/talks.rst:3:Duplicate explicit target name: "slides".

[codecov]

Codecov Report

Merging #4282 into master will decrease coverage by 2.01%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master    #4282      +/-   ##
==========================================
- Coverage   95.87%   93.85%   -2.02%     
==========================================
  Files         109      109              
  Lines       24630    24625       -5     
  Branches     2396     2393       -3     
==========================================
- Hits        23615    23113     -502     
- Misses        720     1182     +462     
- Partials      295      330      +35

Flag	Coverage Δ
#docs	?
#doctesting	?
#linting	?
#linux	93.85% <ø> (-1.78%)	⬇️
#nobyte	?
#numpy	?
#pexpect	?
#py27	91.79% <ø> (-2.27%)	⬇️
#py34	92.22% <ø> (+0.53%)	⬆️
#py35	?
#py36	92.21% <ø> (-1.8%)	⬇️
#py37	?
#trial	?
#windows	?
#xdist	?

Impacted Files	Coverage Δ
testing/test_pdb.py	43.94% <0%> (-51.06%)	⬇️
src/_pytest/debugging.py	63.02% <0%> (-31.1%)	⬇️
testing/python/approx.py	79.84% <0%> (-19.77%)	⬇️
src/_pytest/unittest.py	75.14% <0%> (-19.21%)	⬇️
testing/test_unittest.py	85.32% <0%> (-13.77%)	⬇️
src/_pytest/reports.py	86.9% <0%> (-10.72%)	⬇️
src/_pytest/python_api.py	87.12% <0%> (-10.31%)	⬇️
testing/test_pathlib.py	91.17% <0%> (-8.83%)	⬇️
src/_pytest/assertion/util.py	92.99% <0%> (-5.15%)	⬇️
testing/test_tmpdir.py	94.33% <0%> (-4.41%)	⬇️
... and 21 more

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[nicoddemus]

Fine to leave this as is, just for the record: using __ as suffix (instead of a single _) doesn't generate target names. 😁

[avallbona]

Ok, understood. Thanks @blueyed and @nicoddemus !!