(fix): fix support for Emacs 26 built-in org (#711)

org-make-link-string was changed to org-link-make-string in org 9.3. But Emacs
26 ships with org 9.1. Defining an alias to the old function name when using an
older org version.

Co-authored-by: N V <44036031+progfolio@users.noreply.github.com>

org-roam-compat.el

@@ -80,6 +80,9 @@
 (define-obsolete-function-alias 'org-roam-db--maybe-update 'org-roam-db--update-maybe
   "org-roam 1.1.0")
 
+(when (version< (org-version) "9.3")
+  (defalias 'org-link-make-string 'org-make-link-string))
+
 ;;;; Variables
 (define-obsolete-variable-alias 'org-roam-graphviz-extra-options
   'org-roam-graph-extra-config "org-roam 1.0.0")