add support and CI testing for Python 3.14

`URLopener` has been deprecated for a long time and is now removed. We
were only using it for a version string, and that's easy to reproduce.

Author: oconnor663

.github/workflows/push.yml

@@ -13,7 +13,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        python-version: ["3.8", "3.9", "3.10", "3.11", "3.12", "3.13"]
+        python-version: ["3.8", "3.9", "3.10", "3.11", "3.12", "3.13", "3.14"]
         os: [ubuntu-latest, windows-latest, macOS-latest]
 
     steps:

peru/resources/plugins/curl/curl_plugin.py

@@ -16,11 +16,10 @@
 
 
 def add_user_agent_to_request(request):
-    components = [
-        "peru/%s" % peru.main.get_version(),
-        urllib.request.URLopener.version
-    ]
-    request.add_header("User-agent", " ".join(components))
+    version = peru.main.get_version()
+    pymajor = sys.version_info.major
+    pyminor = sys.version_info.minor
+    request.add_header("User-agent", f"peru/{version} Python-urllib/{pymajor}.{pyminor}")
     return request