[core] Change version string to X.Y.Z

[dpiparo]

from X.Y/Z. Fixes #14068

[github-actions[bot]]

Test Results

    11 files      11 suites   2d 8h 10m 56s :stopwatch:  2 635 tests  2 635 :white_check_mark: 0 :zzz: 0 :x: 27 419 runs  27 419 :white_check_mark: 0 :zzz: 0 :x:

Results for commit fd3fea58.

:recycle: This comment has been updated with latest results.

[dpiparo]

my bad, I need to fix a test.

[dpiparo]

Interesting errors, which were to be expected. The ROOT PCMs have coded the version number with a "/" while after the changes the version does not contain it any more. Given that root pcms are special files, written w/o streamer infos (for performance reasons and because by construction are read only by the same release that produced them) many tests still fail. If the builds were not incremental, the problem would not be there. Thinking about a solution.

[dpiparo]

This webpage will have to be updated as well https://root.cern/about/versioning/

[hahnjo]

Found the issue with this PR, the problem is that TROOT.cxx does the following: https://github.com/root-project/root/blob/95307116ca3dd811ac1b5e496ad7f9828402dc51/core/base/src/TROOT.cxx#L184-L189

This either needs updating or, better yet, use direct arithmetic. Note that the latter may not be trivial because ROOT_VERSION_PATCH may be 08 which isn't a valid octal literal...

Edit: can confirm it passes my local testing after adapting the scanf invocation.