hound: add detect-ref config option

Hound has the ability to query the remote origin and detect the HEAD,
which is useful for projects that don't have the default "master"
branch but have switched to "main".  Add this to the config.

Change-Id: I4bb72b8d65f418b1a0f2f67ab64a8267cd25f2cf
diff --git a/jeepyb/cmd/create_hound_config.py b/jeepyb/cmd/create_hound_config.py
index 373ae02..d5a4581 100644
--- a/jeepyb/cmd/create_hound_config.py
+++ b/jeepyb/cmd/create_hound_config.py
@@ -62,6 +62,11 @@
 
     config = {
         "dbpath": "data",
+        "vcs-config": {
+            "git": {
+                "detect-ref": True
+            }
+        },
         "repos": repos
     }
     with open('config.json', 'w') as config_file: