Use new cmd for nix builds

.drone.yml

@@ -27,8 +27,14 @@ steps:
   volumes:
     - name: deps
       path: /nix/store
+  environment:
+    DRONE_SSH_KEY:
+      from_secret: drone_ssh_key
   commands:
-    - nix-build --argstr version ${DRONE_TAG} --argstr rev ${DRONE_COMMIT} .#image
+    - mkdir /root/.ssh
+    - echo $DRONE_SSH_KEY > /root/.ssh/id_ed25519
+    - echo $GIT_C3C_KNOW_HOSTS > /root/.ssh/known_hosts
+    - nix --extra-experimental-features nix-command --extra-experimental-features flakes build .#image
 
 - name: publish
   image: docker:dind
@@ -85,8 +91,12 @@ services:
   - name: dockersock
     path: /var/run
 
+---
+kind: secret
+name: drone_ssh_key
+data: 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
 ---
 kind: signature
-hmac: df9a2fb07428f545bc41b36d4c8b53e0e7223333f614e2d5d890a1adbd7f324b
+hmac: b992b7c5815edff54cbee13837b65760419a6058da6f98fc45856aa40bf8002d
 
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