Update CONTRIBUTING.

CONTRIBUTING.rst

@@ -19,7 +19,7 @@ Contributing code
 3. Write a test for your new feature/bugfix and run it, ensuring
  that it fails on the current implementation::
 
- py.test tests/test_my_code.py
+ pytest tests/test_my_code.py
 
  NameErrors, ImportErrors, SyntaxErrors, etc. do not count (they indicate the
  API is wrong).
@@ -29,9 +29,7 @@ Contributing code
 
  tox run
 
- Optionally, run integration tests (you must have Redis_ server
- version 2.8 or later in your path; do ``redis-server --version``
- to check)::
+ Optionally, run integration tests::
 
  tox run -- integration-tests
 
@@ -41,10 +39,10 @@ Contributing code
  ``n-issue-abbrev`` where ``n`` is the issue number and
  ``issue-abbrev`` is a very short abbreviation of the issue title)
  and ensure that the build passes. The build is defined in
- ``.gitlab-ci.yml`` (``.travis.yml`` and ``appveyor.yml`` for public
+ ``.gitlab-ci.yml`` (``.github/workflows`` for public
  builds); tox is configured in ``tox.ini``. The build
  includes unit tests, integration tests, and style checks and runs on
- Python 3.5 across multiple platforms; if it fails, please
+ Python 3.8 across multiple platforms; if it fails, please
  find the error in the build log, fix it, and try again.
 9. Add a line to ``CHANGELOG`` under the current version-in-progress
  describing your changes simply and concisely. Add yourself to ``AUTHORS``