Add some SSH keys to tc-mac workers

etc/taskcluster/macos/config/master

@@ -5,6 +5,7 @@ file_roots:
 extension_modules: ../modules
 ext_pillar:
   - taskcluster_secrets:
+  - ssh_keys:
 roster_defaults:
     # https://github.com/saltstack/salt/issues/50477
     minion_opts:

etc/taskcluster/macos/modules/pillar/ssh_keys.py

@@ -0,0 +1,14 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at https://mozilla.org/MPL/2.0/.
+
+import urllib
+
+
+def ext_pillar(_minion_id, _pillar, *_args):
+    url = "https://raw.githubusercontent.com/servo/saltfs/master/admin/files/ssh/%s.pub"
+    return {"ssh_keys": [urllib.urlopen(url % name).read() for name in [
+        "jdm",
+        "manishearth",
+        "simonsapin",
+    ]]}

etc/taskcluster/macos/states/generic-worker.sls

@@ -6,6 +6,14 @@
 GMT:
   timezone.system
 
+sshkeys:
+  ssh_auth.present:
+    - user: root
+    - names:
+    {% for key in pillar["ssh_keys"] %}
+      - {{ key | yaml_encode }}
+    {% endfor %}
+
 {{ bin }}/generic-worker:
   file.managed:
     - name: