Use current Python for coverage instead of oldest available

tox.ini

@@ -48,7 +48,6 @@ skip_install = True
 # by default, coverage should run on oldest supported Python for testing platform coverage.
 # however, coverage for a particular Python version should match the version used for pytest.
 base_python =
-    coverage: py38,py39,py310,py311,py312,py313
     coverage38: py38
     coverage39: py39
     coverage310: py310
@@ -61,6 +60,7 @@ setenv =
     fail: REPORT_FAIL_COND = --fail-under=100
     CORE_RCFILE = --rcfile {tox_root}{/}core{/}pyproject.toml
     PROJECT_RCFILE = --rcfile {tox_root}{/}pyproject.toml
+commands_pre = python --version
 commands =
     -python -m coverage combine {env:CORE_RCFILE} {env:COMBINE_KEEP}
     html: python -m coverage html {env:PROJECT_RCFILE} --skip-covered --skip-empty