Add phpstan-docker-image custom variable, default as official image

README.org

@@ -124,8 +124,13 @@ Rule level of PHPStan analysis.  Please see [[https://github.com/phpstan/phpstan
 
 *** Custom variable ~phpstan-flycheck-auto-set-executable~
 Set flycheck phpstan-executable automatically when non-NIL.
+
 *** Custom variable ~phpstan-memory-limit~
 Use phpstan memory limit option when non-NIL.
 - STRING :: Specifies the memory limit in the same format php.ini accepts.
      - ex) ~"1G"~
 - ~nil~ :: Use memory limit in php.ini
+
+*** Custom variable ~phpstan-docker-image~
+Docker image URL or Docker Hub image name or NIL.  Default as ~"ghcr.io/phpstan/phpstan"~.  See [[https://phpstan.org/user-guide/docker][Docker - PHPStan Documentation]]
+ and [[https://github.com/orgs/phpstan/packages/container/package/phpstan][GitHub Container Registory - Package phpstan]].

phpstan.el

@@ -84,6 +84,18 @@
   :safe (lambda (v) (or (null v) (stringp v)))
   :group 'phpstan)
 
+(defcustom phpstan-docker-image "ghcr.io/phpstan/phpstan"
+  "Docker image URL or Docker Hub image name or NIL."
+  :type '(choice
+          (string :tag "URL or image name of Docker Hub.")
+          (const :tag "Official Docker container" "ghcr.io/phpstan/phpstan")
+          (const :tag "No specify Docker image"))
+  :link '(url-link :tag "PHPStan Documentation" "https://phpstan.org/user-guide/docker")
+  :link '(url-link :tag "GitHub Container Registry"
+                   "https://github.com/orgs/phpstan/packages/container/package/phpstan")
+  :safe (lambda (v) (or (null v) (stringp v)))
+  :group 'phpstan)
+
 ;;;###autoload
 (progn
   (defvar phpstan-working-dir nil
@@ -281,7 +293,7 @@ it returns the value of `SOURCE' as it is."
    ((eq 'docker phpstan-executable)
     (list "run" "--rm" "-v"
           (concat (expand-file-name (php-project-get-root-dir)) ":/app")
-          "phpstan/phpstan"))
+          phpstan-docker-image))
    ((and (consp phpstan-executable)
          (eq 'root (car phpstan-executable)))
     (list