[misc] Run scheduled tests every Saturday

[slarse]

Once a day is way too often.

[codecov]

Codecov Report

Merging #25 (72c0d3a) into master (8c3924c) will increase coverage by 0.38%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master      #25      +/-   ##
==========================================
+ Coverage   96.20%   96.59%   +0.38%     
==========================================
  Files           3        3              
  Lines          79       88       +9     
  Branches       14       15       +1     
==========================================
+ Hits           76       85       +9     
  Misses          2        2              
  Partials        1        1              

Impacted Files	Coverage Δ
repobee_feedback/feedback.py	96.51% <100.00%> (+0.40%)	⬆️

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 04369e5...72c0d3a. Read the comment docs.