chore: remove RUSTFLAGS setting x86-v2 target

Author: mmstick

justfile

@@ -1,14 +1,6 @@
 ID := 'pop-launcher'
 plugins := 'calc desktop_entries files find pop_shell pulse recent scripts terminal web cosmic_toplevel'
 
-x86-64-target := 'x86-64-v2'
-
-export RUSTFLAGS := if arch() == 'x86_64' {
-    ' -C target-cpu=' + x86-64-target
-} else {
-    ''
-}
-
 rootdir := ''
 
 base-dir := if rootdir == '' {