tox: Stop encoding python version in tox envs

This does not seem useful: the CI workflow already picks the python
version specifically.

Signed-off-by: Jussi Kukkonen <jkukkonen@google.com>

.github/workflows/_test.yml

@@ -27,13 +27,13 @@ jobs:
             toxenv: py
           - python-version: "3.13"
             os: ubuntu-latest
-            toxenv: purepy311
+            toxenv: purepy
           - python-version: "3.13"
             os: ubuntu-latest
-            toxenv: py311-no-gpg
+            toxenv: py-no-gpg
           - python-version: "3.13"
             os: ubuntu-latest
-            toxenv: py311-test-gpg-fails
+            toxenv: py-test-gpg-fails
           - python-version: "3.13"
             os: ubuntu-latest
             toxenv: lint

tox.ini

@@ -4,7 +4,7 @@
 # and then run "tox" from this directory.
 
 [tox]
-envlist = lint, py38, py39, py310, py311, purepy311, py311-no-gpg, py311-test-gpg-fails
+envlist = lint, py, purepy, py-no-gpg, py-test-gpg-fails
 skipsdist = True
 
 [testenv]
@@ -23,14 +23,14 @@ commands =
     coverage run tests/aggregate_tests.py
     coverage report -m --fail-under 70
 
-[testenv:purepy311]
+[testenv:purepy]
 deps =
 
 commands =
     python -m tests.check_gpg_available
     python -m tests.check_public_interfaces
 
-[testenv:py311-no-gpg]
+[testenv:py-no-gpg]
 setenv =
     GNUPG = nonexisting-gpg-for-testing
 commands =
@@ -53,7 +53,7 @@ commands =
     python -m tests.check_sigstore_signer
 
 # Check that importing securesystemslib._gpg.constants doesn't shell out.
-[testenv:py311-test-gpg-fails]
+[testenv:py-test-gpg-fails]
 setenv =
     GNUPG = false
 commands =