Set constrain_package_deps in tox.ini

Author: dmtucker

tox.ini

@@ -1,6 +1,6 @@
 # For more information about tox, see https://tox.readthedocs.io/en/latest/
 [tox]
-minversion = 3.20
+minversion = 4.4
 isolated_build = true
 envlist =
     py37-pytest{4.6, 5.0, 5.x, 6.0, 6.x, 7.0, 7.x}-mypy{0.50, 0.x, 1.0, 1.x}
@@ -22,6 +22,7 @@ python =
     3.12: py312-pytest{6.2, 6.x, 7.0, 7.x, 8.0, 8.x}-mypy{0.90, 0.x, 1.0, 1.x}
 
 [testenv]
+constrain_package_deps = true
 deps =
     pytest4.6: pytest ~= 4.6.0
     pytest5.0: pytest ~= 5.0.0
@@ -54,6 +55,7 @@ testpaths = tests
 
 [testenv:publish]
 passenv = TWINE_*
+constrain_package_deps = false
 deps =
     build[virtualenv] ~= 0.9.0
     twine ~= 4.0.0