docs: change references to repo URL

The Nixery main Git repo has moved
from https://github.com/google/nixery
to https://github.com/tazjin/nixery .

So change it in README and on the https://nixery.dev/ website.

tools/nixery/docs/src/nixery.md

@@ -77,7 +77,7 @@ availability.
 Nixery was written by [tazjin][], but many people have contributed to Nix over
 time, maybe you could become one of them?
 
-[Nixery]: https://github.com/google/nixery
+[Nixery]: https://github.com/tazjin/nixery
 [Nix]: https://nixos.org/nix
 [layering strategy]: https://storage.googleapis.com/nixdoc/nixery-layers.html
 [layers]: https://grahamc.com/blog/nix-and-layered-docker-images

tools/nixery/docs/src/run-your-own.md

@@ -181,10 +181,10 @@ If the directory doesn't exist, Nixery will run fine but serve 404.
     extensively.
 
 [GKE]: https://cloud.google.com/kubernetes-engine/
-[nixery#4]: https://github.com/google/nixery/issues/4
+[nixery#4]: https://github.com/tazjin/nixery/issues/4
 [Nix]: https://nixos.org/nix
 [gcs]: https://cloud.google.com/storage/
-[repo]: https://github.com/google/nixery
+[repo]: https://github.com/tazjin/nixery
 [signed-urls]: under-the-hood.html#5-image-layers-are-requested
 [ADC]: https://cloud.google.com/docs/authentication/production#finding_credentials_automatically
 [nixinstall]: https://nixos.org/manual/nix/stable/installation/installing-binary.html