fix(gh-actions): Fix nix flake update action for repos with pre-commit

[galin-s]

No description provided.

[github-actions]

Thanks for your Pull Request!

Below you will find a summary of the cachix status of each package, for each supported platform.

package	x86_64-linux	x86_64-darwin	aarch64-darwin
cachix	❌ build failed	❌ build failed	❌ build failed
dcd	✅ cached	🚫 not supported	🚫 not supported
dmd	✅ cached	🚫 not supported	🚫 not supported
dscanner	✅ cached	🚫 not supported	🚫 not supported
dub	✅ cached	✅ cached	✅ cached
folder-size-metrics	✅ cached	🚫 not supported	🚫 not supported
foundry	✅ cached	✅ cached	✅ cached
geth	✅ cached	🚫 not supported	✅ cached
grafana-agent	✅ cached	🚫 not supported	✅ cached
ldc	✅ cached	🚫 not supported	🚫 not supported
lido-withdrawals-automation	✅ cached	✅ cached	✅ cached
mcl	✅ cached	🚫 not supported	🚫 not supported
mev-boost	✅ cached	🚫 not supported	🚫 not supported
nethermind	✅ cached	🚫 not supported	🚫 not supported
nimbus-eth2	✅ cached	🚫 not supported	🚫 not supported
nix	❌ build failed	❌ build failed	❌ build failed
nix-eval-jobs	✅ cached	✅ cached	❌ build failed
nix-fast-build	✅ cached	✅ cached	❌ build failed
pyroscope	✅ cached	✅ cached	✅ cached
rustToolchain	✅ cached	✅ cached	✅ cached
serve-d	✅ cached	🚫 not supported	🚫 not supported
terraform	✅ cached	🚫 not supported	🚫 not supported
terranix	✅ cached	🚫 not supported	🚫 not supported
validator-ejector	✅ cached	🚫 not supported	🚫 not supported
web3signer	✅ cached	🚫 not supported	🚫 not supported