chore: lowercase GitHub owner links

[bochkov-anton]

Summary

• Updated the GitHub contact links in .github/ISSUE_TEMPLATE/config.yml to use the lowercase owner path https://github.com/arcoris/pool.
• This change is needed because the repository owner was renamed to lowercase, and the issue template should point users to the canonical repository URLs.

Type of change

• Bug fix
• Feature
• Refactor
• Performance improvement
• Documentation change
• Test change
• Build / toolchain change
• CI / automation change
• Chore / maintenance
• Revert

Target branch

• Target branch: main
• This PR targets main
• I did not push directly to the protected branch

Validation

• Local commands run:
  • None
• Additional checks run:
  • Searched the repository for remaining tracked https://github.com/ARCORIS/ references after the update.
• Remaining validation gaps:
  • go test ./... was not run because this PR only updates GitHub URLs in issue template metadata.
  • go test -race ./... was not run because this PR only updates GitHub URLs in issue template metadata.
  • go vet ./... was not run because this PR only updates GitHub URLs in issue template metadata.

Documentation impact

• No documentation changes needed
• Documentation updated in this PR
• Notes:
  • The change is limited to repository issue template contact links.

Release impact

• No release impact
• Patch release impact
• Minor release impact
• Major / breaking change
• Notes:
  • This change only updates GitHub repository links shown from the issue template.

Linked work

• Related issue(s):
  • None
• Related proposal / design note:
  • None

Author checklist

• PR title follows type(scope): summary
• This change is based on a short-lived topic branch created from main
• Tests and checks run locally are listed above
• Docs, comments, or examples were updated where needed
• Release impact is described above