Move CI to Emacs 28 minimum

Author: CeleritasCelery

.github/workflows/test.yml

@@ -22,7 +22,6 @@ jobs:
           #- macos-latest
           #- windows-latest
         emacs-version:
-          - 27.2
           - 28.2
           - 29.4
           - 30.1

rustic.el

@@ -4,7 +4,7 @@
 ;; Author: Mozilla
 ;;
 ;; Keywords: languages
-;; Package-Requires: ((emacs "26.1") (rust-mode "1.0.6") (dash "2.13.0") (f "0.18.2") (let-alist "1.0.4") (markdown-mode "2.3") (project "0.3.0") (s "1.10.0") (spinner "1.7.3") (xterm-color "1.6") (flycheck "34.0"))
+;; Package-Requires: ((emacs "28.2") (rust-mode "1.0.6") (dash "2.13.0") (f "0.18.2") (let-alist "1.0.4") (markdown-mode "2.3") (project "0.3.0") (s "1.10.0") (spinner "1.7.3") (xterm-color "1.6") (flycheck "34.0"))
 
 ;; This file is distributed under the terms of both the MIT license and the
 ;; Apache License (version 2.0).