deps: replace certifi & urllib3 with requests

requirements/base.txt

@@ -44,9 +44,6 @@ django-extensions==2.2.6
 # https://github.com/deschler/django-modeltranslation
 django-modeltranslation==0.16.2
 
-# Certifi, a carefully curated collection of Root Certificates for SSL
-certifi>=2019.11.28
-
 # Faker is a Python package that generates fake data for you.
 # https://faker.readthedocs.io/en/master/
 #
@@ -85,7 +82,9 @@ sortedcontainers==2.1.0
 # https://bitbucket.org/astanin/python-tabulate
 tabulate==0.9.0
 
-urllib3==1.26.5
+# HTTP library
+# https://github.com/psf/requests
+requests==2.31.0
 
 # For upload to Google cloud storage
 google-cloud-storage==1.36.1

src/proposals/management/commands/slack.py

@@ -4,21 +4,17 @@
 """
 import json
 
-import urllib3
-import certifi
+import requests
 
 
 class Slack:
 
     def __init__(self, url):
         """Config a Slack connection"""
         self.url = url
-        # The connection is initiated lazily by urllib3
-        self.pool = urllib3.PoolManager(
-            # Always check the HTTPS certificate
-            cert_reqs='CERT_REQUIRED',
-            ca_certs=certifi.where(),
-        )
+        # The connection is initiated lazily by requests
+        self.session = requests.Session()
+        self.session.headers.update({'Content-Type': "application/json"})
 
     def notify(self, **kwargs):
         """Collect **kwargs as JSON and talk to Slack."""
@@ -31,10 +27,8 @@ def send(self, payload):
         :param: payload:
             A dict-like object passed as JSON content
         """
-        response = self.pool.urlopen(
-            "POST",
+        response = self.session.post(
             self.url,
-            headers={'Content-Type': "application/json"},
-            body=json.dumps(payload)
+            data=json.dumps(payload)
         )
         return response.status, response.data.decode('utf8')