feat: add sprint input action

[lorenzo-ranciaffi]

This PR adds the MODIFIER input action type so that it can be sent as an event by the client

Needed by the request in the CH issue decentraland/creator-hub#428.

[github-actions]

Test this pull request on NPM or Yarn

• The @dcl/protocol package can be tested in scenes by running the following NPM command:

  npm install "https://sdk-team-cdn.decentraland.org/@dcl/protocol/branch//dcl-protocol-1.0.0-19675167055.commit-4f14515.tgz"

• The @dcl/protocol package can be tested in scenes by running the following YARN command:

  yarn add "https://sdk-team-cdn.decentraland.org/@dcl/protocol/branch//dcl-protocol-1.0.0-19675167055.commit-4f14515.tgz"