Updated poetry files with altair

Author: micahkwok

poetry.lock

@@ -12,6 +12,8 @@ pandas = "^1.2.2"
 [tool.poetry.dev-dependencies]
 Sphinx = "^3.5.1"
 sphinxcontrib-napoleon = "^0.7"
+pytest = "^6.2.2"
+altair = "^4.1.0"
 
 [build-system]
 requires = ["poetry-core>=1.0.0"]