Y24-115 - Add a reusable workflow to automate the generation of issue title numbers

[SHIV5T3R]

Closes https://github.com/sanger/General-Backlog-Items/issues/406

Changes proposed in this pull request

• A new workflow that will run when an issue is opened which will increment an organisation variable that tracks the number of issues across the organisation.
• The incremented value will be used to prefix the issue title when an issue number, e.g: Y24-056, Y24-1042.

Instructions for Reviewers

[All PRs] - Confirm PR template filled
[Feature Branches] - Review code
[Production Merges to main]
    - Check story numbers included
    - Check for debug code
    - Check version

[codeclimate[bot]]

Code Climate has analyzed commit c5cdec0e and detected 0 issues on this pull request.

The test coverage on the diff in this pull request is 100.0% (50% is the threshold).

This pull request will bring the total coverage in the repository to 90.8% (0.0% change).

View more on Code Climate.

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 91.21%. Comparing base (9e181d5) to head (c5cdec0).

Additional details and impacted files

```diff @@ Coverage Diff @@ ## develop #1717 +/- ## ======================================== Coverage 91.21% 91.21% ======================================== Files 364 364 Lines 7543 7543 ======================================== Hits 6880 6880 Misses 663 663 ``` | [Flag](https://app.codecov.io/gh/sanger/limber/pull/1717/flags?src=pr&el=flags&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=sanger) | Coverage Δ | | |---|---|---| | [javascript](https://app.codecov.io/gh/sanger/limber/pull/1717/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=sanger) | `93.65% <ø> (ø)` | | | [pull_request](https://app.codecov.io/gh/sanger/limber/pull/1717/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=sanger) | `91.21% <ø> (?)` | | | [push](https://app.codecov.io/gh/sanger/limber/pull/1717/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=sanger) | `91.21% <ø> (ø)` | | | [ruby](https://app.codecov.io/gh/sanger/limber/pull/1717/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=sanger) | `90.86% <ø> (ø)` | | Flags with carried forward coverage won't be shown. [Click here](https://docs.codecov.io/docs/carryforward-flags?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=sanger#carryforward-flags-in-the-pull-request-comment) to find out more.

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