Add a note on Python 3.10 deprecation

Signed-off-by: Carmen Bianca BAKKER <[email protected]>

pyproject.toml

@@ -58,6 +58,8 @@ binaryornot = ">=0.4.4"
 "boolean.py" = ">=3.8"
 license-expression = ">=1.0"
 python-debian = ">=0.1.34,!=0.1.45,!=0.1.46,!=0.1.47"
+# TODO: Consider removing this dependency in favour of tomllib when dropping
+# Python 3.10.
 tomlkit = ">=0.8"
 attrs = ">=21.3"