Increase minimum Requests version to 2.19

With Python 3.7 and Requests 2.4.0 on Ubuntu 20.04 there are two test
failures; reasons not immediately clear. There is a warning for the use
of ABCs from collections and not collections.abc. That will cause an
exception on Python 3.10 and is fixed in Requests 2.19.0.

pyproject.toml

@@ -21,7 +21,7 @@ classifiers = [
 requires-python = ">=3.7"
 
 dependencies = [
-    "requests >= 2.4",
+    "requests >= 2.19",
     "dnspython >= 2.0",
     "beautifulsoup4 >= 4.8.1",
 ]

requirements-min.txt

@@ -1,6 +1,6 @@
 # required:
 beautifulsoup4 == 4.8.1
-requests == 2.4.0
+requests == 2.19.0
 dnspython == 2.0.0
 # optional:
 argcomplete == 1.8.1

requirements.txt

@@ -1,6 +1,6 @@
 # required:
 beautifulsoup4 >= 4.8.1
-requests >= 2.4
+requests >= 2.19
 dnspython >= 2.0
 # optional:
 argcomplete >= 1.8.1