Merge pull request #333 from flox/release-1.7.4

bump: 1.7.3 -> 1.7.4

Author: devusb

FLOX_VERSION

@@ -1 +1 @@
-1.7.3
+1.7.4

docs/concepts/packages-and-catalog.md

@@ -26,7 +26,7 @@ Packages are declared in the [environment manifest][manifest_concept].
 The built-in catalog is called the Base Catalog, and contains a wide variety of open source packages you can use in your environments.
 The Base Catalog uses [nixpkgs][nixpkgs] as an input.
 Nixpkgs is a community maintained project, but the Base Catalog is maintained by Flox.
-Upstream changes in [nixpkgs][nixpkgs] are reflected in the Flox Catalog daily from the `unstable` branch of [nixpkgs][nixpkgs].
+Upstream changes in [nixpkgs][nixpkgs] are reflected in the Flox Catalog daily from the `nixos-unstable` branch of [nixpkgs][nixpkgs].
 
 ## Supported package metadata