feat: update .envrc

- Remove deprecated nix_direnv_watch_file call
- Update nix-direnv version to 3.0.6

Author: aldoborrero

.envrc

@@ -1,5 +1,5 @@
-if ! has nix_direnv_version || ! nix_direnv_version 2.2.0; then
-    source_url "https://raw.githubusercontent.com/nix-community/nix-direnv/2.2.0/direnvrc" "sha256-5EwyKnkJNQeXrRkYbwwRBcXbibosCJqyIUuz9Xq+LRc="
+if ! has nix_direnv_version || ! nix_direnv_version 3.0.6; then
+  source_url "https://raw.githubusercontent.com/nix-community/nix-direnv/3.0.6/direnvrc" "sha256-RYcUJaRMf8oF5LznDrlCXbkOQrywm0HDv1VjYGaJGdM="
 fi
-nix_direnv_watch_file ./flake-shell.nix
+
 use flake