feat: Expose important library versions

Update `/api/version` to include

```
"other": {
    "xml2rfc": "<version>",
    "weasyprint": "<version>"
},
```

Fixes ietf-tools#3415

ietf/__init__.py

@@ -35,6 +35,21 @@
     __release_branch__ = branch
     __release_hash__ = git_hash
 
+# important libraries
+__version_extra__ = {}
+# xml2rfc
+try:
+    import xml2rfc
+    __version_extra__['xml2rfc'] = xml2rfc.__version__
+except Exception:
+    pass
+
+# weasyprint
+try:
+    import weasyprint
+    __version_extra__['weasyprint'] = weasyprint.__version__
+except Exception:
+    pass
 
 # This will make sure the app is always imported when
 # Django starts so that shared_task will use this app.

ietf/api/tests.py

@@ -872,13 +872,16 @@ def test_api_version(self):
         r = self.client.get(url)
         data = r.json()
         self.assertEqual(data['version'], ietf.__version__+ietf.__patch__)
+        self.assertEqual(data['other']['xml2rfc'], ietf.__version_extra__['xml2rfc'])
+        self.assertEqual(data['other']['weasyprint'], ietf.__version_extra__['weasyprint'])
         self.assertEqual(data['dumptime'], "2022-08-31 07:10:01 +0000")
         DumpInfo.objects.update(tz='PST8PDT')
         r = self.client.get(url)
         data = r.json()        
         self.assertEqual(data['dumptime'], "2022-08-31 07:10:01 -0700")
 
 
+
     def test_api_appauth(self):
         url = urlreverse('ietf.api.views.app_auth')
         person = PersonFactory()

ietf/api/views.py

@@ -243,6 +243,7 @@ def version(request):
     return HttpResponse(
             json.dumps({
                         'version': ietf.__version__+ietf.__patch__,
+                        'other': ietf.__version_extra__,
                         'dumptime': dumptime,
                     }),
                 content_type='application/json',