add notice to use [tool:pytest] in setup.cfg

[Handsome2734]

Notice to use [tool:pytest] in setup.cfg, cause [pytest] is no longer supported.

[codecov]

Codecov Report

Merging #4819 into master will decrease coverage by 0.09%.
The diff coverage is n/a.

@@            Coverage Diff            @@
##           master    #4819     +/-   ##
=========================================
- Coverage   95.74%   95.65%   -0.1%     
=========================================
  Files         113      113             
  Lines       25666    25163    -503     
  Branches     2505     2498      -7     
=========================================
- Hits        24575    24069    -506     
  Misses        772      772             
- Partials      319      322      +3

Flag	Coverage Δ
#docs	29.59% <ø> (+0.1%)	⬆️
#doctesting	29.59% <ø> (+0.1%)	⬆️
#linting	29.59% <ø> (+0.1%)	⬆️
#linux	95.48% <ø> (-0.11%)	⬇️
#nobyte	92.21% <ø> (ø)	⬆️
#numpy	93% <ø> (+0.02%)	⬆️
#pexpect	41.98% <ø> (+0.02%)	⬆️
#pluggymaster	93.72% <ø> (+0.07%)	⬆️
#py27	93.68% <ø> (+0.02%)	⬆️
#py34	91.59% <ø> (ø)	⬆️
#py35	91.62% <ø> (ø)	⬆️
#py36	91.64% <ø> (ø)	⬆️
#py37	93.82% <ø> (+0.01%)	⬆️
#py38	?
#trial	93% <ø> (+0.02%)	⬆️
#windows	93.68% <ø> (ø)	⬆️
#xdist	93.69% <ø> (-0.16%)	⬇️

Impacted Files	Coverage Δ
testing/test_modimport.py	81.81% <0%> (-1.52%)	⬇️
testing/code/test_source.py	95.53% <0%> (-1.07%)	⬇️
src/_pytest/cacheprovider.py	96.22% <0%> (-1%)	⬇️
testing/test_argcomplete.py	68.11% <0%> (-0.9%)	⬇️
testing/test_compat.py	91.13% <0%> (-0.63%)	⬇️
testing/test_skipping.py	97.65% <0%> (-0.57%)	⬇️
src/_pytest/warnings.py	88.88% <0%> (-0.53%)	⬇️
src/_pytest/debugging.py	77.98% <0%> (-0.41%)	⬇️
src/_pytest/fixtures.py	97.91% <0%> (-0.31%)	⬇️
src/_pytest/logging.py	94.96% <0%> (-0.31%)	⬇️
... and 73 more

---

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Δ = absolute <relative> (impact), ø = not affected, ? = missing data
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[codecov]

Codecov Report

Merging #4819 into master will decrease coverage by 0.08%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master    #4819      +/-   ##
==========================================
- Coverage   95.74%   95.66%   -0.09%     
==========================================
  Files         113      113              
  Lines       25666    25163     -503     
  Branches     2505     2498       -7     
==========================================
- Hits        24575    24071     -504     
  Misses        772      772              
- Partials      319      320       +1

Flag	Coverage Δ
#docs	29.59% <ø> (+0.1%)	⬆️
#doctesting	29.59% <ø> (+0.1%)	⬆️
#linting	29.59% <ø> (+0.1%)	⬆️
#linux	95.49% <ø> (-0.1%)	⬇️
#nobyte	92.21% <ø> (ø)	⬆️
#numpy	93% <ø> (+0.02%)	⬆️
#pexpect	41.98% <ø> (+0.02%)	⬆️
#pluggymaster	93.72% <ø> (+0.07%)	⬆️
#py27	93.68% <ø> (+0.03%)	⬆️
#py34	91.59% <ø> (ø)	⬆️
#py35	91.61% <ø> (-0.01%)	⬇️
#py36	91.64% <ø> (ø)	⬆️
#py37	93.82% <ø> (+0.01%)	⬆️
#py38	?
#trial	93% <ø> (+0.02%)	⬆️
#windows	93.67% <ø> (ø)	⬆️
#xdist	93.7% <ø> (-0.16%)	⬇️

Impacted Files	Coverage Δ
testing/test_modimport.py	81.81% <0%> (-1.52%)	⬇️
testing/code/test_source.py	95.53% <0%> (-1.07%)	⬇️
testing/test_argcomplete.py	68.11% <0%> (-0.9%)	⬇️
testing/test_compat.py	91.13% <0%> (-0.63%)	⬇️
testing/test_skipping.py	97.65% <0%> (-0.57%)	⬇️
src/_pytest/warnings.py	88.88% <0%> (-0.53%)	⬇️
src/_pytest/debugging.py	77.98% <0%> (-0.41%)	⬇️
src/_pytest/fixtures.py	97.91% <0%> (-0.31%)	⬇️
src/_pytest/logging.py	94.96% <0%> (-0.31%)	⬇️
testing/test_assertrewrite.py	83.55% <0%> (-0.3%)	⬇️
... and 73 more

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 1cf9c2e...3e11bd0. Read the comment docs.