fix(models): fill in OffensiveSecurityTime

[MaineK00n]

What did you implement:

When I looked in the DB, I found that the date: OffensiveSecurityTime part was null. This has been fixed.

Type of change

• [x] Bug fix (non-breaking change which fixes an issue)

How Has This Been Tested?

// upstream/master: go-exploitdb fetch exploitdb
$ sqlite3 go-exploitdb.sqlite3
SQLite version 3.31.1 2020-01-27 19:55:54
Enter ".help" for usage hints.
sqlite> select offensive_security_id, date from documents LIMIT 3;
offensive_security_id|date
1|
2|
3|

// PR: go-exploitdb fetch exploitdb
$ sqlite3 go-exploitdb.sqlite3
sqlite> select offensive_security_id, date from documents LIMIT 3;
offensive_security_id|date
1|2008-06-22 00:00:00+00:00
2|2008-06-22 00:00:00+00:00
3|2016-06-06 00:00:00+00:00

Checklist:

You don't have to satisfy all of the following.

• [ ] Write tests
• [ ] Write documentation
• [x] Check that there aren't other open pull requests for the same issue/feature
• [x] Format your source code by make fmt
• [x] Pass the test by make test
• [x] Provide verification config / commands
• [x] Enable "Allow edits from maintainers" for this PR
• [x] Update the messages below

Is this ready for review?: YES

Reference