Add pytest-instafail to environment.yml (pandas-dev#36686)

Author: dsaxton

environment.yml

@@ -58,6 +58,7 @@ dependencies:
   - pytest-cov
   - pytest-xdist>=1.21
   - pytest-asyncio
+  - pytest-instafail
 
   # downstream tests
   - seaborn

requirements-dev.txt

@@ -39,6 +39,7 @@ pytest>=5.0.1
 pytest-cov
 pytest-xdist>=1.21
 pytest-asyncio
+pytest-instafail
 seaborn
 statsmodels
 ipywidgets