- src/ppdm.c: own PPDM_VERSION (0.0.1, overridable) + 'ppdm -v'; rename pmu->ppdm
with pack/update commands (see previous commit).
- release.yml: build ppdm with -DPPDM_VERSION=\"0.0.1\" (own version, independent of PMM).
- PMM site version -> 0.5.5 (this release also ships the ppdm 0.0.1 asset).
- CHANGELOG/0.5.5.md.