ci(.radicle/ambient.yaml): fix so CI can succeed under new Ambient

.radicle/ambient.yaml

@@ -3,7 +3,18 @@ pre_plan:
 plan:
   - action: cargo_fmt
   - action: cargo_clippy
-  - action: cargo_test
+    
+  # Can't use the cargo_test action, until HOME is set
+  # in the environment.
+  - action: shell
+    shell: |
+      export HOME=/root
+      # "Install" the rad program. It needs to be in $PATH.
+      cp /root/.radicle/bin/rad /bin/.
+      git config --global user.name root
+      git config --global user.email root@example.com
+      cargo test
+
   - action: cargo_doc
   - action: custom
     name: dch