WIP: Single SemVer bump per release

[s0ders]

What type of PR is this?

fix and refactor

What this PR does / why is it needed:

1. Makes the project compliant with the SemVer specification by only bumping once per release (choosing the higher type of bump for each release) as suggested by @dionysiusmarquis
2. Only fetch the latest reachable tag for each branch being processed, which removes various bug linked to the order in which branches are processed.
3. The parser not longer checks out to a branch to get its commits but uses its references, removes the issue of temporary files added in the repository before the program run (e.g., GPG key or whatever) disapearing after the check out and also makes the program more efficient.

Does this PR introduce a breaking change?

Yes, will upgrade the Go module version from v6 to v7.

Note to self

• Try to handle prerelease bumps
• Refactor the tests "framework" and tests in general for better maintainability

[codecov]

Codecov Report

❌ Patch coverage is 93.22034% with 4 lines in your changes missing coverage. Please review.
✅ Project coverage is 82.11%. Comparing base (dca1ae8) to head (3f99a27).
⚠️ Report is 13 commits behind head on main.

Files with missing lines	Patch %	Lines
internal/parser/parser.go	94.82%	3 Missing ⚠️
internal/monorepo/flag.go	0.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #217      +/-   ##
==========================================
+ Coverage   78.36%   82.11%   +3.74%     
==========================================
  Files          14       14              
  Lines         772      615     -157     
==========================================
- Hits          605      505     -100     
+ Misses        120       66      -54     
+ Partials       47       44       -3     

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