cachix/devenv v2.3.1 on GitHub

Fixed cachix.pull containing duplicate caches. The module adds devenv (and cachix.push) to the list, so a cache also listed in devenv.nix was registered twice and Nix warned Substituter '...' is already present in the substituters list on every command. The option now deduplicates its value.
Fixed devenv no longer fetching the public signing keys of the caches in cachix.pull, a regression from the 2.0 rewrite. Only keys already present in cachix_trusted_keys.json were passed to Nix, so on a machine that had only ever run 2.x extra-trusted-public-keys was empty and Nix could not verify paths from those caches. The keys are fetched from the Cachix API again (using the resolved auth token for private caches) and cached (#3176).