docs: Add award number for second phase of IRIS-HEP

[alexander-held]

Description

Adding the award number for the second phase of IRIS-HEP to the readme. I only saw the award number from the first phase mentioned in one other place, the JOSS acknowledgements, but those were prior work so I don't think it makes sense to update there.

Checklist Before Requesting Reviewer

• Tests are passing
• "WIP" removed from the title of the pull request
• Selected an Assignee for the PR to be responsible for the log summary

Before Merging

For the PR Assignees:

• Summarize commit messages into a comprehensive review of the PR

* Add badge and funding acknowledgement for NSF cooperative agreement
  PHY-2323298 award for IRIS-HEP v2.
   - c.f. https://www.nsf.gov/awardsearch/showAward?AWD_ID=2323298

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Comparison is base (2eb13e8) 98.28% compared to head (565d7e3) 98.28%.
Report is 1 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #2354   +/-   ##
=======================================
  Coverage   98.28%   98.28%           
=======================================
  Files          69       69           
  Lines        4538     4538           
  Branches      803      803           
=======================================
  Hits         4460     4460           
  Misses         45       45           
  Partials       33       33           

Flag	Coverage Δ
contrib	97.86% <ø> (ø)
doctest	60.70% <ø> (ø)
unittests-3.10	96.29% <ø> (ø)
unittests-3.11	96.29% <ø> (ø)
unittests-3.8	96.31% <ø> (ø)
unittests-3.9	96.34% <ø> (ø)

Flags with carried forward coverage won't be shown. Click here to find out more.

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

[matthewfeickert]

Thanks @alexander-held! This had been on my TODO list.