Use the master constraint in tox.ini again

While releasing a new tag for Tempest, we modified the
constraint in tox.ini so that they are set to wallaby instead of
master - https://review.opendev.org/c/openstack/tempest/+/783319

Now the new tag is released and we can bring back the master
constraint in tox.ini so that Tempest master uses master constraint.

Change-Id: I3e5202076c0d318e41218af3ea181a2f2985abec
diff --git a/tox.ini b/tox.ini
index d4789a5..2315163 100644
--- a/tox.ini
+++ b/tox.ini
@@ -11,7 +11,7 @@
     VIRTUAL_ENV={envdir}
     OS_TEST_PATH=./tempest/test_discover
 deps =
-    -c{env:UPPER_CONSTRAINTS_FILE:https://releases.openstack.org/constraints/upper/wallaby}
+    -c{env:UPPER_CONSTRAINTS_FILE:https://releases.openstack.org/constraints/upper/master}
     -r{toxinidir}/requirements.txt
 
 [testenv]
@@ -28,7 +28,7 @@
 install_command = pip install {opts} {packages}
 allowlist_externals = *
 deps =
-    -c{env:UPPER_CONSTRAINTS_FILE:https://releases.openstack.org/constraints/upper/wallaby}
+    -c{env:UPPER_CONSTRAINTS_FILE:https://releases.openstack.org/constraints/upper/master}
     -r{toxinidir}/requirements.txt
     -r{toxinidir}/test-requirements.txt
 commands =
@@ -263,7 +263,7 @@
 
 [testenv:venv]
 deps =
-  -c{env:UPPER_CONSTRAINTS_FILE:https://releases.openstack.org/constraints/upper/wallaby}
+  -c{env:UPPER_CONSTRAINTS_FILE:https://releases.openstack.org/constraints/upper/master}
   -r{toxinidir}/requirements.txt
   -r{toxinidir}/doc/requirements.txt
 commands = {posargs}
@@ -278,7 +278,7 @@
 
 [testenv:docs]
 deps =
-  -c{env:UPPER_CONSTRAINTS_FILE:https://releases.openstack.org/constraints/upper/wallaby}
+  -c{env:UPPER_CONSTRAINTS_FILE:https://releases.openstack.org/constraints/upper/master}
   -r{toxinidir}/doc/requirements.txt
 commands =
   sphinx-apidoc -f -o doc/source/tests/compute tempest/api/compute
@@ -363,7 +363,7 @@
 
 [testenv:releasenotes]
 deps =
-  -c{env:UPPER_CONSTRAINTS_FILE:https://releases.openstack.org/constraints/upper/wallaby}
+  -c{env:UPPER_CONSTRAINTS_FILE:https://releases.openstack.org/constraints/upper/master}
   -r{toxinidir}/doc/requirements.txt
 commands =
   rm -rf releasenotes/build