Install setuptools

It seems the setuptools library is no longer installed by default.

tox.ini

@@ -10,6 +10,7 @@ passenv =
     GNOCCHI_TEST_*
     AWS_*
 setenv =
+    VIRTUALENV_SETUPTOOLS=bundle
     GNOCCHI_TEST_STORAGE_DRIVER=file
     GNOCCHI_TEST_INDEXER_DRIVER=postgresql
     GNOCCHI_TEST_STORAGE_DRIVERS=file swift ceph s3 redis
@@ -69,6 +70,7 @@ deps =
 recreate = True
 setenv =
     GNOCCHI_VERSION_FROM=stable/4.5
+    VIRTUALENV_SETUPTOOLS=bundle
     GNOCCHI_VARIANT=test,postgresql,file
 deps =
     gnocchiclient>=2.8.0,!=7.0.7
@@ -82,6 +84,7 @@ allowlist_externals = {toxinidir}/run-upgrade-tests.sh
 # Gnocchi we can't reuse the virtualenv
 recreate = True
 setenv =
+    VIRTUALENV_SETUPTOOLS=bundle
     GNOCCHI_VERSION_FROM=stable/4.5
     GNOCCHI_VARIANT=test,mysql,ceph,ceph_recommended_lib
 deps =
@@ -103,6 +106,7 @@ allowlist_externals =
 
 [testenv:{py39,py311}-cover]
 setenv =
+    VIRTUALENV_SETUPTOOLS=bundle
     {[testenv]setenv}
     PYTHON=coverage run --source gnocchi --parallel-mode
 commands =
@@ -131,6 +135,7 @@ deps =
     .[test,file,postgresql,doc]
     doc8
 setenv =
+    VIRTUALENV_SETUPTOOLS=bundle
     GNOCCHI_TEST_DEBUG=1
 commands =
     doc8 --ignore-path doc/source/rest.rst,doc/source/comparison-table.rst doc/source
@@ -141,11 +146,11 @@ allowlist_externals =
     /bin/bash
     /bin/rm
 setenv =
+    VIRTUALENV_SETUPTOOLS=bundle
     GNOCCHI_STORAGE_DEPS=file
     GNOCCHI_TEST_DEBUG=1
 deps =
     {[testenv:docs]deps}
-    setuptools
 commands =
     /bin/rm -rf doc/build/html
     pifpaf -g GNOCCHI_INDEXER_URL run postgresql -- sphinx-build -W --keep-going -b html -j auto doc/source doc/build/html