meta: drop Python 3.7 support

In an effort to support the future (i.e. Sopel 8 and modern tooling),
Python 3.7 is now dropped for official support.

People using Sopel 7.1 can still use the perfectly fine previous version
0.4.0 of this plugin. Since Sopel 8 drops support for Py3.7, this
shouldn't be a problem for the future.

.github/workflows/ci.yml

@@ -19,7 +19,6 @@ jobs:
     strategy:
       matrix:
         python-version:
-          - "3.7"
           - "3.8"
           - "3.9"
           - "3.10"

README.rst

@@ -15,7 +15,7 @@ The recommanded way to install this plugin is to use ``pip``::
 
     $ pip install sopel-help
 
-Note that this plugin requires Python 3.7+ and Sopel 7.1+.
+Note that this plugin requires Python 3.8+ and Sopel 7.1+.
 
 Configure
 =========

pyproject.toml

@@ -30,14 +30,13 @@ classifiers = [
     "License :: Eiffel Forum License (EFL)",
     "License :: OSI Approved :: Eiffel Forum License",
     "Operating System :: POSIX :: Linux",
-    "Programming Language :: Python :: 3.7",
     "Programming Language :: Python :: 3.8",
     "Programming Language :: Python :: 3.9",
     "Programming Language :: Python :: 3.10",
     "Programming Language :: Python :: 3.11",
     "Topic :: Communications :: Chat :: Internet Relay Chat",
 ]
-requires-python = ">=3.7"
+requires-python = ">=3.8"
 dependencies = [
     "sopel>=7.1",
     "requests",