ci: set 'omitBody' true when releasing

[zyy17]

I hereby agree to the terms of the GreptimeDB CLA

What's changed and what's your intention?

set 'omitBody' true when releasing

Please explain IN DETAIL what the changes are in this PR and why they are needed:

• Summarize your change (mandatory)
• How does this PR work? Need a brief introduction for the changed logic (optional)
• Describe clearly one logical change and avoid lazy messages (optional)
• Describe any limitations of the current code (optional)

Checklist

• I have written the necessary rustdoc comments.
• I have added the necessary unit tests and integration tests.

Refer to a related PR or issue link (optional)

[codecov]

Codecov Report

Merging #2845 (4ef456d) into develop (ae81535) will decrease coverage by 0.32%.
The diff coverage is n/a.

Additional details and impacted files

@@             Coverage Diff             @@
##           develop    #2845      +/-   ##
===========================================
- Coverage    84.79%   84.47%   -0.32%     
===========================================
  Files          737      737              
  Lines       115840   115840              
===========================================
- Hits         98224    97859     -365     
- Misses       17616    17981     +365