fix: record each platform's own list version

install/<platform>.json wrote the constant "1.0" as the version of the
list it was built from. The manifest now carries the version the platform
YAML records, and generate_pack refuses a YAML without one.

inherits: no longer passes a parent's version to a child: Lakka was
published as RetroArch v1.22.2 in its manifest, pack name and site page.
lakka.yml records v6.1, the Lakka-LibreELEC tag its target list is read
at. The MiSTer scraper refuses a BiosDB without a timestamp instead of
writing an empty version.

A pack's manifest.json records list_version, so an install from the pack
alone knows it too. Manifests regenerated twice and compared: only
version and generated changed.

scripts/common.py

@@ -235,6 +235,10 @@ def _inherited_yaml(platform_name: str, platforms_dir: str) -> tuple[dict, list[
         return config, [platform_name]
 
     merged, chain = _inherited_yaml(config["inherits"], platforms_dir)
+    # A version names one platform's release, never its parent's: Lakka
+    # read as RetroArch v1.22.2 in its manifest, pack name and site page.
+    # dat_version stays, it is the version of the inherited list itself.
+    merged.pop("version", None)
     merged.update(
         {k: v for k, v in config.items() if k not in ("inherits", "overrides")}
     )