More information about the changes at https://github.com/zeitgeistpm/zeitgeist/releases/tag/v0.3.5

 Reject a proposed spend. The original deposit will be slashed.

 May only be called from `T::RejectOrigin`.

 # <weight>
 - Complexity: O(1)
 - DbReads: `Proposals`, `rejected proposer account`
 - DbWrites: `Proposals`, `rejected proposer account`
 # </weight>

Problem Statement:
- Lack of information about changes at Zeitgeist v0.3.5 release.

Significance:
- Users and developers of Zeitgeist need to be aware of the changes in the v0.3.5 release.

Proposed Solution:
- Provide more information about the changes at Zeitgeist v0.3.5 release.

Expected Outcomes:
- Increased awareness and understanding of the changes in the v0.3.5 release.

#10 Authorize Zeitgeist runtime v0.3.5 upgrade