offline deploy nightly dm cluster failed.

Bug Report

Please answer these questions before submitting your issue. Thanks!

1. What did you do?

tiup mirror clone tidb-dm-nightly-linux-amd64 --os=linux --arch=amd64 \
    --dm-master=nightly --dm-worker=nightly --dmctl=nightly \
    --alertmanager=v0.17.0 --grafana=nightly --prometheus=nightly \
    --tiup=v$(tiup --version|grep 'tiup'|awk -F ' ' '{print $1}') --dm=v$(tiup --version|grep 'tiup'|awk -F ' ' '{print $1}')

cd tidb-dm-nightly-linux-amd64
./local_install.sh
tiup dm deploy dm_cluster nightly ./dm_cluster.yaml --user gmhdbjd -p

2. What did you expect to see?
   deploy successfully
   tiup --version should be 1.4.2

3. What did you see instead?

Error: component prometheus doesn't has a stable version

Error: component grafana doesn't has a stable version

1.4.0 tiup
Go Version: go1.16.2
Git Ref: v1.4.0
GitHash: eb335e6ad9d0dc19d1c43db422cd409d62bc3cea

4. What version of TiUP are you using (tiup --version)?
   1.4.2

Start by reproducing the commands in the report, especially tiup mirror clone, local_install.sh, and the dm_cluster.yaml deployment. Compare the reported TiUP versions and the Prometheus and Grafana stable-version errors; done means the offline deployment succeeds without those errors and TiUP reports the expected version.