fix(ci): Small bugs in release checkeer

[tore-espressif]

• Number of commits defaults to "0" for nicer output
• Git log is invoked with -m to also process merge commits. This is important for:
  • Getting precise release date. The release happens after the commit is merged into master
  • Getting correct order of commits. Omitting 'merge commit' in the history can lead to incorrect order of commits, as they are sorted by their creation time, rather their merge time

[espzav]

@tore-espressif Thank you! LGTM

[github-actions]

Test Results

28 tests   28 ✅  1m 32s ⏱️
 5 suites   0 💤
 5 files     0 ❌

Results for commit ef73a70.