Add nix flake update to upgrade instructions (#125)

Nix does not always update transitive dependencies of an input per flox/flox#2457 Running `nix flake lock --update-input flox` didn't fix the issue, but we think `nix flake update` did.
flox · Feb 5, 2025 · f4ccf25 · f4ccf25
1 parent ed156f4
commit f4ccf25
Showing 1 changed file with 4 additions and 0 deletions.
diff --git a/docs/install-flox.md b/docs/install-flox.md
@@ -675,6 +675,10 @@ description: Install or upgrade Flox
     ...
     ```
 
+    Nix does not always update transitive dependencies when the version is
+    changed,
+    so to ensure all updates are applied, run `nix flake update`.
+
 ## Uninstall Flox
 
 While we are sad we see you uninstalling `flox` we would like **thank you**