add dev dependencies

CHANGELOG.md

@@ -13,6 +13,7 @@
 - Adding basic switch tag handle
 - Adding failsafe for non defined sys.stdout.buffer
 - Adding list of tikz color
+- Adding dev dependencies group in the pyproject.toml
 ### Changed
 - Using style from new inkex
 - Using path from new inkex

docs/contribute.rst

@@ -11,9 +11,11 @@ We used black_ and pylint_ to format and lint the code. Github actions are run o
 .. _black: https://github.com/psf/black
 .. _pylint: https://github.com/pylint-dev/pylint
 
+You can directly install the dev depedencies with `poetry install --with dev`
+
 Tests
 =====
-The tests of SVG2TikZ are writting using the unittest_ package. You can run all the test with command `python -m unittest`.
+The tests of SVG2TikZ are writting using the unittest package. You can run all the test with command `python -m unittest`.
 
 
 .. _unittest: https://docs.python.org/3/library/unittest.html