Add missing call to load_azp_token

Author: ianwallen

docs/pipelines/agents/docker.md

@@ -376,6 +376,9 @@ Next, create the Dockerfile.
       echo 1>&2 "error: missing AZP_URL environment variable"
       exit 1
     fi
+
+    # Let load azp token for initial setup.
+    load_azp_token
     
     if [ -n "${AZP_WORK}" ]; then
       mkdir -p "${AZP_WORK}"