Fix DMSP SSUSI file format change

[aburrell]

Description

Addresses #239 by adding file handing for the change in file format across a specific date.

Type of change

Please delete options that are not relevant.

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• This change requires a documentation update

How Has This Been Tested?

import datetime as dt
import pysat
import pysatNASA

ssusi = pysat.Instrument(inst_module=pysatNASA.instruments.dmsp_ssusi, tag='sdr-disk', inst_id='f18')

stime = dt.datetime(2023, 3, 20)
etime = dt.datetime(2023, 3, 25)

ssusi.download(start=stime, stop=etime)
ssusi.files.files

Yields:

2023-03-20 00:53:14    dmspf18_ssusi_sdr-disk_2023079T005314-2023079T...
2023-03-20 12:06:22    dmspf18_ssusi_sdr-disk_2023079T120622-2023079T...
2023-03-20 12:46:42    dmspf18_ssusi_sdr-disk_2023079T124642-2023079T...
2023-03-20 14:28:38    dmspf18_ssusi_sdr-disk_2023079T142838-2023079T...
2023-03-20 16:10:34    dmspf18_ssusi_sdr-disk_2023079T161034-2023079T...
                                             ...                        
2023-03-25 16:46:45    dmspf18_ssusi_sdr-disk_2023084T164645-2023084T...
2023-03-25 18:35:39    dmspf18_ssusi_sdr-disk_2023084T183539-2023084T...
2023-03-25 20:10:37    dmspf18_ssusi_sdr-disk_2023084T201037-2023084T...
2023-03-25 21:52:33    dmspf18_ssusi_sdr-disk_2023084T215233-2023084T...
2023-03-25 23:34:29    dmspf18_ssusi_sdr-disk_2023084T233429-2023085T...
Length: 73, dtype: object

Checked SPDF and the other SSUSI instruments also have the change in format at this time.

Test Configuration:

• Operating system: OS X Big Sur
• Version number: Python 3.10
• Any details about your local setup that are relevant: develop branch of pysat

Checklist:

• x] Make sure you are merging into the develop (not main) branch
• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes
• Any dependent changes have been merged and published in downstream modules
• Add a note to CHANGELOG.md, summarizing the changes
• Update zenodo.json file for new code contributors

If this is a release PR, replace the first item of the above checklist with the release
checklist on the wiki: https://github.com/pysat/pysat/wiki/Checklist-for-Release

[jklenzing]

Broken doc tests have been fixed in the main rc branch. Thanks!