chore: add alias 'flakeup' using direnv to quickly upgrade nix packages

.envrc

@@ -0,0 +1,32 @@
+# ~/.direnvrc
+
+# Clear existing aliases when entering a directory
+
+export tmpdir="$(mktemp -d -t dots-alias-direnv.XXXXXX)"
+rm -rf "/tmp/dots-alias-direnv.*"
+
+export_alias() {
+  # Create a new alias
+  local name=$1
+  shift
+
+  local alias_dir="$tmpdir/.envrc-aliases"
+  local alias_file="$alias_dir/$name"
+  local oldpath="$PATH"
+
+  # If this is the first time we're calling export_alias, add to PATH once
+  if ! [[ ":$PATH:" == *":$alias_dir:"* ]]; then
+    mkdir -p "$alias_dir"
+    PATH_add "$alias_dir"
+  fi
+
+  # Write the alias file
+  cat <<EOT >$alias_file
+#!/usr/bin/env bash
+PATH="$oldpath"
+$@
+EOT
+  chmod +x "$alias_file"
+}
+
+export_alias flakeup 'nix flake update && git commit flake.lock -m "nix: update flake to latest unstable nixpkgs" && FLAKE=$PWD nh os switch'