Change release workflow to use new staging bucket for artifacts

[gaiksaya]

Issue #, if available:

Description of changes:
The infrastructure team is separating the production and staging locations into different AWS accounts. Plugins need to modify their workflows to publish to the new locations.

This PR changes the CD workflow to add a build number and write the zip, deb, and rpm plugin artifacts to staging.artifacts.opendistroforelasticsearch.amazon.com.

Test Results
https://github.com/gaiksaya/alerting/runs/1672094597?check_suite_focus=true

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.

[codecov]

Codecov Report

Merging #334 (612f516) into master (908b627) will decrease coverage by 0.03%.
The diff coverage is n/a.

@@             Coverage Diff              @@
##             master     #334      +/-   ##
============================================
- Coverage     79.32%   79.28%   -0.04%     
+ Complexity      203      202       -1     
============================================
  Files           151      151              
  Lines          5324     5324              
  Branches        701      701              
============================================
- Hits           4223     4221       -2     
- Misses          727      728       +1     
- Partials        374      375       +1     

Impacted Files	Coverage Δ	Complexity Δ
...ing/destination/client/DestinationEmailClient.java	72.50% <0.00%> (-5.00%)	7.00% <0.00%> (-1.00%)
...distroforelasticsearch/alerting/util/IndexUtils.kt	71.42% <0.00%> (-2.39%)	0.00% <0.00%> (ø%)
...distroforelasticsearch/alerting/core/JobSweeper.kt	72.19% <0.00%> (+0.53%)	35.00% <0.00%> (ø%)

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 908b627...612f516. Read the comment docs.