Merge pull request #197 from graingert/fix-tox-docs

update tox docs to python 3.8

Author: graingert

Diff for: CONTRIBUTING.rst

@@ -20,7 +20,7 @@ Development environment
 
 Tox is used to manage both local development and CI environment.
 
-The recommended local dev enviroment is `tox -e py27-test-dev`
+The recommended local dev enviroment is `tox -e py38-test-dev`
 
 When running on local dev env, you will get a coverage report for whole
 code as well as for the changes since `master`.
@@ -32,8 +32,8 @@ The reports are also produced in HTML at:
 You can run a subset of the test by passing the dotted path to the test or
 test case, test module or test package::
 
-    tox -e py27-test-dev ldaptor.test.test_delta.TestModifyOp.testAsLDIF
-    tox -e py27-test-dev ldaptor.test.test_usage
+    tox -e py38-test-dev ldaptor.test.test_delta.TestModifyOp.testAsLDIF
+    tox -e py38-test-dev ldaptor.test.test_usage
 
 
 Release notes