Don't set SETUPTOOLS_USE_DISTUTILS on newer Sphinx testenvs.

Author: domdfcoding

tox.ini

@@ -265,6 +265,9 @@ addopts = --color yes --durations 25
 timeout = 300
 
 [testenv:py{39,310,311,312,313,py39}-sphinx7.2]
+setenv =
+    PYTHONDEVMODE=1
+    PIP_DISABLE_PIP_VERSION_CHECK=1
 deps =
     -r{toxinidir}/tests/requirements.txt
     -r{toxinidir}/requirements.txt
@@ -275,6 +278,9 @@ commands =
     python -m pytest --cov=sphinxcontrib.default_values -r aR tests/ {posargs}
 
 [testenv:py{39,310,311,312,313,py39}-sphinx7.3]
+setenv =
+    PYTHONDEVMODE=1
+    PIP_DISABLE_PIP_VERSION_CHECK=1
 deps =
     -r{toxinidir}/tests/requirements.txt
     -r{toxinidir}/requirements.txt
@@ -285,6 +291,9 @@ commands =
     python -m pytest --cov=sphinxcontrib.default_values -r aR tests/ {posargs}
 
 [testenv:py{39,310,311,312,313,py39}-sphinx7.4]
+setenv =
+    PYTHONDEVMODE=1
+    PIP_DISABLE_PIP_VERSION_CHECK=1
 deps =
     -r{toxinidir}/tests/requirements.txt
     -r{toxinidir}/requirements.txt
@@ -295,6 +304,9 @@ commands =
     python -m pytest --cov=sphinxcontrib.default_values -r aR tests/ {posargs}
 
 [testenv:py{310,311,312,313}-sphinx8.0]
+setenv =
+    PYTHONDEVMODE=1
+    PIP_DISABLE_PIP_VERSION_CHECK=1
 deps =
     -r{toxinidir}/tests/requirements.txt
     -r{toxinidir}/requirements.txt
@@ -305,6 +317,9 @@ commands =
     python -m pytest --cov=sphinxcontrib.default_values -r aR tests/ {posargs}
 
 [testenv:py{310,311,312,313}-sphinx8.1]
+setenv =
+    PYTHONDEVMODE=1
+    PIP_DISABLE_PIP_VERSION_CHECK=1
 deps =
     -r{toxinidir}/tests/requirements.txt
     -r{toxinidir}/requirements.txt
@@ -315,6 +330,9 @@ commands =
     python -m pytest --cov=sphinxcontrib.default_values -r aR tests/ {posargs}
 
 [testenv:py{311,312,313}-sphinx8.2]
+setenv =
+    PYTHONDEVMODE=1
+    PIP_DISABLE_PIP_VERSION_CHECK=1
 deps =
     -r{toxinidir}/tests/requirements.txt
     -r{toxinidir}/requirements.txt