Rename label for delayed unassigned shards

[therealdwright]

Closes #310

This has been tested on my Elasticsearch 7.13.0 cluster deployed using ECK. I have now got unique metrics for unassigned shards and delayed unassigned shards. These can be queried in prometheus using:

avg(es_cluster_shards_number{cluster="example",type="unassigned"})

and

avg(es_cluster_shards_number{cluster="example",type="delayed_unassigned"})

I've also produced a simple dashboard that works for the current metrics/labels. Please let me know if you want this PR'ed in to the repo.

[therealdwright]

Hi @lukas-vlcek and @vvanholl,

I'm wondering if there is any appetite to merge this (very) minor change? We would like to use the upstream repository rather than a fork and this is the only thing that is in the way.

Thanks.

[therealdwright]

Hello @lukas-vlcek and @vvanholl,

Could you please let me know if this is something that your project does not wish to accept? I'll close the PR if this is the case.

[lukas-vlcek]

@therealdwright Do not close it please.
I will review asap.

[therealdwright]

Hello @lukas-vlcek and @vvanholl,

I'd like to again ask for an update please. Does this PR have any chance of being merged?

[therealdwright]

Closing as it does not seem there is any interest in this PR.

[mindw]

@therealdwright a friendly fork of this repo with the above change (and many others) is maintained by me at https://github.com/mindw/elasticsearch-prometheus-exporter FYI.