Remove pyXX prefix for lint, docs, and coverage

tox.ini

@@ -7,16 +7,19 @@ testdeps =
 [tox]
 envlist =
     py{37,38,39,310}
-    py38-lint
-    py38-coverage
-    py38-docs
+    lint
+    coverage
+    docs
+
+ignore_basepython_conflict = true
 
 [testenv]
+basepython=python3.8
 deps = {[base]testdeps}
 extras = plotly
 commands = pytest {posargs}
 
-[testenv:py38-lint]
+[testenv:lint]
 deps =
     pycodestyle
     pydocstyle
@@ -27,7 +30,7 @@ commands =
     pydocstyle --match-dir='(?!test).*' {toxinidir}/neurom
     pylint --rcfile=pylintrc --extension-pkg-whitelist=numpy --ignore=tests neurom
 
-[testenv:py38-coverage]
+[testenv:coverage]
 deps =
     {[base]testdeps}
     pytest-cov
@@ -38,7 +41,7 @@ commands =
     --cov-fail-under=100 \
     --cov-report=xml
 
-[testenv:py38-docs]
+[testenv:docs]
 changedir = doc
 extras = docs
 commands =
@@ -59,6 +62,6 @@ convention = google
 [gh-actions]
 python =
   3.7: py37
-  3.8: py38
+  3.8: py38, lint, docs, coverage
   3.9: py39
   3.10: py310