ci: remove unused secrets from dryrun steps

.drone.yml

@@ -34,11 +34,7 @@ steps:
         - BUILD_VERSION=${DRONE_TAG%-*}
       dockerfile: Dockerfile
       dry_run: true
-      password:
-        from_secret: docker_password
       repo: thegeeklab/${DRONE_REPO_NAME}
-      username:
-        from_secret: docker_username
     when:
       ref:
         - refs/pull/**
@@ -201,6 +197,6 @@ depends_on:
 
 ---
 kind: signature
-hmac: 42ec3e3517c9b8207612b0a3d89fd34d02290babd557063ac941d7b94edc65d5
+hmac: 07c057dfd06b861ee2213ff0f86e517c52aea018985cd84d90c69c7d21483116
 
 ...