Update to Postgres 14 as required by main

[aspark21]

plugin installs against main branch of moodle are failing since the postgres 14 requirement has been integrated

  Output:                                                                      
  ================                                                             
  == Environment ==                                                            
  !! database postgres (13.18 (Debian 13.18-1.pgdg120+1)) !!                   
  [System] version 14 is required and you are running 13.18 -                  

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 88.34%. Comparing base (18fe3e1) to head (292d1e1).
Report is 7 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff            @@
##               main     #333   +/-   ##
=========================================
  Coverage     88.34%   88.34%           
  Complexity      757      757           
=========================================
  Files            77       77           
  Lines          2333     2333           
=========================================
  Hits           2061     2061           
  Misses          272      272           

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

[kabalin]

Thanks for updating template! (related GHA change was made in #336)