feat(versioning): same major

[RahulGautamSingh]

Changes

• Add a helper function massageVersion which massages single versions to constrains. eg. X.Y.Z as >=X.Y.Z <X+1.0.0

• Modify some methods so that they can handle the version as a constraint and work as expected.
  For eg. matches should return true for matches('1.1.0', '1.0.0');
  For more examples, please see the tests.

Context

Closes: #27312

Documentation (please check one with an [x])

• I have updated the documentation, or
• No documentation update is required

How I've tested my work (please select one)

I have verified these changes via:

• Code inspection only, or
• Newly added/modified unit tests, or
• No unit tests but ran on a real repository, or
• Both unit tests + ran on a real repository
  https://github.com/Rahul-renovate-testing/same-major
  First I ran with latest version which created 2 PRs: i) for the highest version with same major and ii) with the latest version
  Then I ran with new changes ie. versioning: same-major and PR i) was autoclosed

[viceice]

shouldn't we name it semver-same-major or semver-coerced-same-major?

Or at least the docs need to clarify that semver-coerced versioning is used under the hood

[secustor]

Nitpick, but not blocking

[HonkingGoose]

The docs are hard to understand.

Please add some examples that explain how it works. Like maybe a diff of "old dependency" vs "proposed Renovate update".

Also focus on the reader, what problem is this feature fixing, how to use/configure it, and how to know if it's working as intended.

[HonkingGoose]

Some style fixes for the current text. I still find this hard to read and understand.