fix CI fails

We want to use a newer version of modus-theme, adding pin to force
emacs to install it from gnu.

lisp/init-local.el

@@ -32,10 +32,10 @@
 ;; Use Protesilaos Stavrou’s lovely modus-operandi https://gitlab.com/protesilaos/modus-themes
 ;;; For the built-in themes which cannot use `require'.
 
-(use-package emacs
+(use-package modus-themes
+  :ensure t
+  :pin gnu
   :config
-  (require-theme 'modus-themes) ; `require-theme' is ONLY for the built-in Modus themes
-
   ;; Add all your customizations prior to loading the themes
   (setq modus-themes-italic-constructs t
         modus-themes-bold-constructs nil)