Mark deprecated fields with deprecated option in protobuf

[Copilot]

This PR adds the protobuf deprecated option to properly mark deprecated fields and message types in the dispatch API schema.

Changes Made

1. CategorySet message: Added option deprecated = true; to mark the entire message type as deprecated
2. component_categories field: Added [deprecated = true] to mark the field as deprecated
3. Release Notes: Updated RELEASE_NOTES.md to document the deprecation changes

Before

// Deprecated: Use `CategoryTypeSet` instead
message CategorySet {
  // Set of component categories
  repeated frequenz.api.common.v1alpha8.microgrid.electrical_components
      .ElectricalComponentCategory categories = 1;
}

// Deprecated: Component categories
// Use `CategoryTypeSet` instead  
// In future versions, this field will be removed.
CategorySet component_categories = 2;

After

// Deprecated: Use `CategoryTypeSet` instead
message CategorySet {
  option deprecated = true;
  // Set of component categories
  repeated frequenz.api.common.v1alpha8.microgrid.electrical_components
      .ElectricalComponentCategory categories = 1;
}

// Deprecated: Component categories
// Use `CategoryTypeSet` instead
// In future versions, this field will be removed.
CategorySet component_categories = 2 [deprecated = true];

Benefits

• Clear deprecation signaling: Code generators will now properly mark these elements as deprecated in generated client libraries
• Developer warnings: Developers using these deprecated fields will receive appropriate deprecation warnings
• API clarity: Makes the deprecation status explicit in the protobuf schema itself, not just in comments
• Future-proof: Prepares for eventual removal of these deprecated elements

The changes follow the official protobuf specification for marking deprecated elements and maintain full backward compatibility while providing clear deprecation signals to API consumers.

Fixes #252.

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[Copilot]

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[Marenz]

Looks good but also update the RELEASE_NOTES.md file

[Marenz]

@copilot please update the release notes file

[Copilot]

@copilot please update the release notes file

Updated the RELEASE_NOTES.md file to document the protobuf deprecation changes in commit 17bdc11.

[Copilot]

Pull Request Overview

This PR properly marks deprecated protobuf elements with the official deprecated option to provide clear deprecation signals to API consumers and code generators.

• Added option deprecated = true; to the CategorySet message
• Added [deprecated = true] to the component_categories field in TargetComponents
• Updated release notes to document the deprecation changes

Reviewed Changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated no comments.

File	Description
proto/frequenz/api/dispatch/v1/dispatch.proto	Added protobuf deprecation options to CategorySet message and component_categories field
RELEASE_NOTES.md	Documented the deprecation changes for API consumers