Bugfix #2437 main_v11.0 convert

[JohnHalleyGotway]

Expected Differences

• Do these changes introduce new tools, command line arguments, or configuration file options? [No]
  
  If yes, please describe:
  

• Do these changes modify the structure of existing or add new output data types (e.g. statistic line types or NetCDF variables)? [No]
  
  If yes, please describe:
  

Pull Request Testing

• Describe testing already performed for these changes:
  

Manually tested using a single monthly input file.

The differences flagged in the GHA run for this PR are the addition of 4 new output files, as expected:

ERROR: folder /data/output/met_test_truth missing 4 files
    climatology_2.5deg/grid_stat_SINGLE_MONTH_CLIMO_2.5DEG_000000L_20201225_120000V.stat
    climatology_2.5deg/grid_stat_SINGLE_MONTH_CLIMO_2.5DEG_000000L_20201225_120000V_pairs.nc
    climatology_2.5deg/grid_stat_WRAP_YEAR_CLIMO_2.5DEG_000000L_20201225_120000V.stat
    climatology_2.5deg/grid_stat_WRAP_YEAR_CLIMO_2.5DEG_000000L_20201225_120000V_pairs.nc

And changing the FCST_UNITS and OBS_UNITS in existing output files is also flagged, as expected:

ERROR: header information mismatch in column FCST_UNITS

• Recommend testing for the reviewer(s) to perform, including the location of input datasets, and any additional instructions:
  

You can test these code on seneca as the met_test user in:
/d1/projects/MET/MET_pull_requests/met-11.0.1/issue_2437/MET-main_v11.0_2437_develop_convert

You could test additional dates, including leap years, and pay close attention to the "Skipping", "Storing", "Shifting", and "Interpolating" log messages to confirm that the logic is working as expected.

• Do these changes include sufficient documentation updates, ensuring that no errors or warnings exist in the build of the documentation? [Yes]

• Do these changes include sufficient testing updates? [Yes]

• Will this PR result in changes to the test suite? [Yes]
  
  If yes, describe the new output and/or changes to the existing output:
  

Adds a new call to Grid-Stat to run an existing unit test but with 1 monthly climo input time instead of 2.

• Please complete this pull request review by [Thurs 2/9/23].
  

Pull Request Checklist

See the METplus Workflow for details.

• Review the source issue metadata (required labels, projects, and milestone).
• Complete the PR definition above.
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• Define the PR metadata, as permissions allow.
  Select: Reviewer(s)
  Select: Organization level software support Project or Repository level development cycle Project
  Select: Milestone as the version that will include these changes
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• Close the linked issue and delete your feature or bugfix branch from GitHub.

[j-opatz]

As updated in the develop PR, this PR will still experience issues for date interpolation, but not because of the coding. Rather, the data being tested has irregularities for dates on the 18z variables.
In the same way the develop bugfix was approved, this PR is also approved as it meets the requested outcomes of the bugfix issue.