pocket-casts: Update pocket-casts-desktop-app to 0.9.0

The dependencies were updated with "flatpak-node-generator npm ..."
except the node-gyp module which uses an unsupported installation method
and for which the definitions were copy/pasted from the old build
instructions before running the dependencies script.

NotImplementedError: Git sources in lockfile v2 format are not supported yet (package node_modules/@electron/node-gyp in pocket-casts-desktop-app/package-lock.json)

See flatpak/flatpak-builder-tools#381