5.0.0-rc3: add versions of GCC and Clang packages to central README

New candidate to test updated trunk of ldmx-sw and to include the update to use scikit-hep when isntalling python packages.
Only available by name

just use ldmx/dev:5.0.0-rc3

---

Draft Release Notes

The motivation for this to be a major release is the large changes in the underlying dependencies.

• Updating the OS to Ubuntu 24.04 brought with it a newer GNU compiler, Clang, Python, Boost, and CMake
• Being forced to updated ROOT due to the newer compiler, we choose to jump to 6.34.04 which is relatively recent but also standardizes the RNTuple on disk format. This opens the door to stably transitioning ldmx-sw to use RNTuple instead of TTree under-the-hood if desirable.
• GENIE Generator and Reweight were introduced along with HEPMC3 for more detailed e-N studies
• Acts was brought back into the image from ldmx-sw which saves about 25% (~20min -> ~15min) of compiling time.
• Installing scikit-hep for python also brings in a few more HEP-focused python packages that weren't previously in the image (e.g. awkward).
• nlohmann/json is now installed at the system level since ROOT uses it (and we would like to use it for event visualization purposes)

⚡ Big Stuff

• Update OS to Ubuntu 24.04 and ROOT to 6.34.02 by @tvami in #103
• Addition of HEPMC3 and GENIE Reweight by @wesketchum in #105
  • I had to manually merge this in a weird way and so the PR did not register as "merged" by GitHub but @wesketchum still did all of the work of figuring out how to configure these new packages.
• Refactor Building CI to track ldmx-sw by @tomeichlersmith in #109
• Include Acts, Bump Catch2, Don't use PYTHONPATH too early by @tomeichlersmith in #115
• install nlohmann/json from package like ROOT does by @tomeichlersmith in #117
• tidy python packages to only do main, parent packages by @tomeichlersmith in #120

🧹 Chores

• add two latest releases of ldmx-sw to testing list by @tomeichlersmith in #98
• Bump docker/build-push-action from 5 to 6 by @dependabot in #100
• Auto ldmx-sw Version Update by @github-actions in #114
• doc updates for website and image specification by @tomeichlersmith in #112
• deduce tags before building even though they aren't used by @tomeichlersmith in 44862bd
• Bump extractions/setup-just from 2 to 3 by @dependabot in #118
• Auto ldmx-sw Version Update by @github-actions in #121
• Add tags with the v prefix by @tomeichlersmith in 18c4b3c

New Contributors

• @tvami made their first contribution in #103
• @github-actions made their first contribution in #114

Full Changelog: 4.2.2...5.0.0