chore: Modified bug issue template to add checkbox to report potential regression.

[ashishdhingra]

Issue #, if available:

Description of changes:

• Modified bug issue template to add checkbox to report potential regression.
• Added GitHub action to add/remove label potential-regression when issue is created/edited.

NOTE:

• The GitHub action code was ported from CDK repo.
• The label potential-regression would need to be created manually (we could use color #FF6700 and description Marking this issue as a potential regression to be checked by team member to make it consistent across SDK repos)

Label potential-regression would make issue standout in the list and help engineers to handle high severity issues effectively.

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