Drop support for older Python versions

Author: ThiefMaster

.github/workflows/ci.yml

@@ -11,7 +11,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        python-version: ['3.9', '3.10', '3.11', '3.12']
+        python-version: ['3.12']
 
     services:
       postgres:

README.md

@@ -33,7 +33,7 @@ decided (still work in progress!).
 
 ## Development
 
-We chose Python 3.12 as the backend language, so make sure you have it installed (3.9-3.11 should work as well). To prepare the development environment it is enough to run `make` which takes care of installing all required dependencies inside a new virtualenv. Typically that will be the `.venv` directory unless you override the environment variable `VENV` *e.g.* `VENV=.virtualenv make`. Activate your virtualenv using ``source .venv/bin/activate`` since this is required to run the various `flask` comments that come later.
+We chose Python 3.12 as the backend language, so make sure you have it installed (`pyenv` helps if your distribution does not include it). To prepare the development environment it is enough to run `make` which takes care of installing all required dependencies inside a new virtualenv. Typically that will be the `.venv` directory unless you override the environment variable `VENV` *e.g.* `VENV=.virtualenv make`. Activate your virtualenv using ``source .venv/bin/activate`` since this is required to run the various `flask` comments that come later.
 
 Make sure you have the `python` binary in your PATH. You can also use the `PYTHON` environment variable to override the location of the
 `python` binary. *e.g.:*

setup.cfg

@@ -13,4 +13,4 @@ url = https://github.com/indico/newdle
 packages = find:
 zip_safe = false
 include_package_data = true
-python_requires = ~=3.9
+python_requires = ~=3.12