Fix formatting error

for 'program:dask-worker.command' is badly formatted: unsupported format character ':' (0x3a) at index 276 in section 'program:dask-worker' (file: '/etc/supervisor/supervisord.conf'

Author: oshadura

docker/k8s-worker/supervisord.conf

@@ -68,7 +68,7 @@ serverurl=unix:///tmp/supervisor.sock ; use a unix:// URL  for a unix socket
 
 ; Adding (ENV_WORKER_ID) should fixes https://github.com/CoffeaTeam/jhub/issues/37
 [program:dask-worker]
-command=/bin/bash -c "dask-worker tls://%(ENV_HOST_IP)s:8786 --nthreads 2 --tls-ca-file %(ENV_CERT_DIR)s/..data/ca.pem --tls-cert %(ENV_CERT_DIR)s/..data/hostcert.pem --tls-key %(ENV_CERT_DIR)s/..data/hostcert.pem --nanny --nanny-port 8001 --nanny-contact-address tls://%(ENV_HOST_IP):8001 --listen-address tls://0.0.0.0:8788 --name kubernetes-worker-%(ENV_WORKER_ID)s --contact-address tls://%(ENV_WORKER_IP)s:8788"
+command=/bin/bash -c "dask-worker tls://%(ENV_HOST_IP)s:8786 --nthreads 2 --tls-ca-file %(ENV_CERT_DIR)s/..data/ca.pem --tls-cert %(ENV_CERT_DIR)s/..data/hostcert.pem --tls-key %(ENV_CERT_DIR)s/..data/hostcert.pem --nanny --nanny-port 8001 --nanny-contact-address tls://%(ENV_HOST_IP)s:8001 --listen-address tls://0.0.0.0:8788 --name kubernetes-worker-%(ENV_WORKER_ID)s --contact-address tls://%(ENV_WORKER_IP)s:8788"
 startretries=100
 autostart=true
 autorestart=true