Switch to version 10.3.0-rc.0

[bruno-at-orange]

Prepare release candidate 0 for 10.3.0

• change only the version number

[marcboulle]

LGTM

[popescu-v]

conda-build moved from 24.11.2 to 25.1.1, which entails that Conda packages now have the .conda extension by default, instead of .tar.bz2.

Compare:

• the previous build for 10.6.0-b.0:
  • version of conda-build: https://github.com/KhiopsML/khiops/actions/runs/12690326153/job/35372162667#step:6:39
  • existence of *.tar.bz2 packages: https://github.com/KhiopsML/khiops/actions/runs/12690326153/job/35372162667#step:9:1365
• the current 10.3.0-rc.0 build:
  • version of conda-build: https://github.com/KhiopsML/khiops/actions/runs/12946474520/job/36116084136#step:6:39
  • existence of *.conda packages and absence of *.tar.bz2 packages: https://github.com/KhiopsML/khiops/actions/runs/12946474520/job/36116084136#step:9:1330

Hence, we need to either:

1. pin conda-build to the latest 24.x.y which builds into the tar.bz2 format by default.
2. add the --pkg-format=tar.bz2 option to conda build in

   khiops/.github/workflows/conda.yml

   Line 81 in 3760d03

   conda build --output-folder ./build/conda ./packaging/conda

   (see warning in the last successful build using the .tar.bz2 format: https://github.com/KhiopsML/khiops/actions/runs/12690326153/job/35372162667#step:9:11).
3. update

   khiops/.github/workflows/conda.yml

   Line 175 in 3760d03

   rm -f -v ./build/conda/*/kni-transfer*.tar.bz2

   and

   khiops/.github/workflows/conda.yml

   Line 177 in 3760d03

   --user "$ANACONDA_CHANNEL" ./build/conda/*/*.tar.bz2

   to change from *.tar.bz2 to *.conda.

I would go for either 2. or 3, with a preference for option 2., because it is the least intrusive IMHO, and keeping the .tar.bz2 format would facilitate local manual debugging by eased unarchiving of the packages.