feat(release): add automated nightly releases

[orhun]

As discussed in the last meeting, this PR updates the release workflow (cd.yml) for creating periodic nightly releases.

The version schema is <version>-alpha.<num> and <num> is increased each time the workflow runs. It is also possible to trigger a nightly release manually via the GitHub interface (see workflow_dispatch).

Tested here: https://github.com/orhun/tui-rs-revival/tags

Closes #147

[codecov]

Codecov Report

Merging #359 (1daf6be) into main (440f62f) will increase coverage by 0.23%.
Report is 8 commits behind head on main.
The diff coverage is n/a.

@@            Coverage Diff             @@
##             main     #359      +/-   ##
==========================================
+ Coverage   84.76%   84.99%   +0.23%     
==========================================
  Files          40       40              
  Lines        8603     8686      +83     
==========================================
+ Hits         7292     7383      +91     
+ Misses       1311     1303       -8     

see 2 files with indirect coverage changes

[joshka]

Semver suggests that 0.22.0-whatever is before 0.22.0. We should go to 0.22.1-alpha.0 from 0.22.0.

Otherwise, looks good.

[joshka]

LGTM ααα