diff --git a/rebuild b/rebuild
index 3ed3821..8b577fe 100644
--- a/rebuild
+++ b/rebuild
@@ -2,4 +2,4 @@
 # when dependencies of the charm change,
 # but nothing in the charm needs to.
 # simply change the uuid to something new
-53a3cc06-1178-11ec-a0a4-d3f9c5859dca
+dacdf39c-3d21-11ee-9d14-9bcd8b9057b2
diff --git a/src/build.lock b/src/build.lock
index 5edf7aa..0965332 100644
--- a/src/build.lock
+++ b/src/build.lock
@@ -225,6 +225,12 @@
       "package": "pyaml",
       "vcs": null,
       "version": "21.10.1"
+    },
+    {
+      "type": "python_module",
+      "package": "Cython",
+      "vcs": null,
+      "version": "0.29.36"
     }
   ]
 }
diff --git a/tox.ini b/tox.ini
index 782b398..ff8c050 100644
--- a/tox.ini
+++ b/tox.ini
@@ -92,7 +92,8 @@ commands = stestr run --slowest {posargs}
 [testenv:pep8]
 basepython = python3
 deps = flake8==3.9.2
-       charm-tools==2.8.3
+       PyYAML==6.0.1
+       charm-tools==2.8.6
 commands = flake8 {posargs} src unit_tests
 
 [testenv:func-target]