update security scan / jira integration workflows

[braxex]

Description

The workflow wasn't running when we wanted it to, was erroneously assigning @BearHanded instead of @kx6z, and needed to have custom field selection IDs updated.

Changes made:

• Snyk & SecurityHub workflow cron jobs updated to run daily at 6am UTC.
• Auto-assignee is now Rehman instead of Brendan.
• Custom Application field selection ID is now correct for this app.
• Update workflow filenames to be more descriptive.

PS - Do you like this PR? If so, you're in luck -- there's a matching one in each repo for you to review and approve!

Related ticket(s)

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How to test

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Important updates

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Author checklist

• I have performed a self-review of my code
• I have added thorough tests, if necessary
• I have updated relevant documentation, if necessary

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convert to a different template: test → val | val → prod

[codeclimate]

Code Climate has analyzed commit 86db3bc and detected 0 issues on this pull request.

The test coverage on the diff in this pull request is 100.0% (90% is the threshold).

This pull request will bring the total coverage in the repository to 55.6% (0.0% change).

View more on Code Climate.