tox: add toml test envs

Add four toml test environments, testing that osbuild.util.toml works
for reading and writing with all our supported toml module combinations.

tox.ini

@@ -74,3 +74,44 @@ deps =
 
 commands =
     bash -c 'python -m mypy --follow-imports=skip --disallow-untyped-calls --disallow-untyped-defs --disallow-incomplete-defs {env:TYPEABLES_STRICT}'
+
+[testenv:tomllib]
+description = "test osbuild.util.toml with tomllib"
+deps =
+    pytest
+    mako
+    tomli-w
+
+commands =
+    python -m pytest -s -vvv -k test_util_toml
+
+[testenv:tomli]
+description = "test osbuild.util.toml with tomli"
+deps =
+    pytest
+    tomli
+    tomli-w
+    mako
+
+commands =
+    python -m pytest -s -vvv -k test_util_toml
+
+[testenv:toml]
+description = "test osbuild.util.toml with toml"
+deps =
+    pytest
+    toml
+    mako
+
+commands =
+    python -m pytest -s -vvv -k test_util_toml
+
+[testenv:pytoml]
+description = "test osbuild.util.toml with pytoml"
+deps =
+    pytest
+    pytoml
+    mako
+
+commands =
+    python -m pytest -s -vvv -k test_util_toml