add missing colorama dependency for isort

isort[colors] recently removed their dependency on colorama. Add it back
until isort releases their fix to restore the dependency.

Signed-off-by: Taylor Madore <tmadore@redhat.com>

tox.ini

@@ -44,8 +44,10 @@ commands =
 
 [testenv:isort]
 skip_install = true
+# Remove colorama after https://github.com/PyCQA/isort/issues/2211 is released
 deps =
     isort[colors]
+    colorama
 commands =
     isort --check --diff --color cachito tests