Bump golang version to v21

[Tankilevitch]

Description

What -

• Bumped golang version v21
• Resolve security vulnerabilities
• Bumped workflows to point to v21
• Fixed Entity resource Id generation ( aligned it with the importState method which concatenates the blueprint identifier with the entity identifier )
• Fixes the following -

Why -
How -

Type of change

Please leave one option from the following and delete the rest:

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Non-breaking change (fix of existing functionality that will not change current behavior)
• Documentation (added/updated documentation)