drop support for python < 3.9

Author: beaufour

pyproject.toml

@@ -12,7 +12,7 @@ repository = "https://github.com/beaufour/flickr-download"
 flickr_download = "flickr_download.flick_download:main"
 
 [tool.poetry.dependencies]
-python = "^3.7"
+python = ">=3.9,<4.0"
 flickr-api = "^0.7.7"
 python-dateutil = "^2.8.1"
 PyYAML = ">=5.3,<7.0"