lock tahoe-great-black-swamp to a public resource

flake.lock

@@ -502,10 +502,13 @@
         ]
       },
       "locked": {
-        "lastModified": 1683050544,
-        "narHash": "sha256-P08OTDBLUtwxp1scC44/xiGVZFYaKEu0Ad/E6nsmGgg=",
+        "lastModified": 1683141130,
+        "narHash": "sha256-9fWUAGdKSxA3HU2FGUx77Yp53JjfNa/eE/7FayDVTx8=",
+        "ref": "client-test",
+        "rev": "07cc12f92fa5dcf84dc844db9d94d5656fb908f9",
+        "revCount": 152,
         "type": "git",
-        "url": "file:///home/exarkun/Work/PrivateStorage/tahoe-great-black-swamp"
+        "url": "https://whetstone.private.storage/PrivateStorage/tahoe-great-black-swamp"
       },
       "original": {
         "ref": "client-test",