ci: streamline the main branch workflow to just deploy snapshots

[jponge]

There are already PR checks to run tests on multiple JDKs and check compatibility. This will save some significant CI time by just deploying snapshots.

[codecov]

Codecov Report

Merging #1354 (f9c213d) into main (2f0106d) will increase coverage by 0.10%.
The diff coverage is n/a.

❗ Current head f9c213d differs from pull request most recent head 495dcf1. Consider uploading reports for the commit 495dcf1 to get more accurate results

Additional details and impacted files

@@             Coverage Diff              @@
##               main    #1354      +/-   ##
============================================
+ Coverage     89.83%   89.93%   +0.10%     
- Complexity     3350     3362      +12     
============================================
  Files           459      459              
  Lines         13325    13325              
  Branches       1655     1655              
============================================
+ Hits          11970    11984      +14     
+ Misses          698      694       -4     
+ Partials        657      647      -10     

see 14 files with indirect coverage changes