Golang release staging branch/smithy dafny standard library/0.3.0

[ShubhamChaturvedi7]

Issue #, if available:

Description of changes:

1. Changelog was manually edited.
2. The diff part is broken in the GHA - but changes look fine here
3. git-cliff should be dropped as it adds unnecessary info.

Squash/merge commit message, if applicable:

<type>(dafny/java/python/dotnet/go/rust): <description>

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.

[rishav-karanjit]

LGTM