feat(Spanner): add samples for jsonb

[NivedhaSenthil]

Description

Fixes #<ISSUE-NUMBER>

Note: It's a good idea to open an issue first for discussion.

Checklist

• [ ] Tests pass
• [ ] Lint pass: bundle exec rubocop
• [ ] Please merge this PR for me once it is approved.

[snippet-bot[bot]]

Here is the summary of changes.

You are about to add 3 region tags.

• spanner/spanner_postgresql_jsonb_add_column.rb:15, tag spanner_postgresql_jsonb_add_column
• spanner/spanner_postgresql_jsonb_query_parameter.rb:15, tag spanner_postgresql_jsonb_query_parameter
• spanner/spanner_postgresql_jsonb_update_data.rb:15, tag spanner_postgresql_jsonb_update_data

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