Add issue-id template variable

[okdas]

We need to programmatically generate some URLs to point to the different development dashboards (we provision new environment for each PR). issue-id variable would become handy. Will test this change in the near future.

[okdas]

Tested here: okdas/test-actions#1 (comment)

@dessant Please let me know if there's anything else needs to be done to get this in. Thanks!

[Olshansk]

@dessant Bump

[Olshansk]

@okdas Bump #2

[okdas]

I've discovered this only replaces the first mention of {issue-id}, so we need to change the implementation.
pokt-network/poktroll#567 (comment)

[okdas]

Modified the replace() calls to use global regular expressions (/g flag) instead of string literals. This ensures all instances of {issue-author} and {issue-id} are replaced, not just the first occurrence.

Here's an example of working global replace: pokt-network/poktroll#702 (comment)

@dessant can we get this in please?