Explicitly install tcl-tk9

Co-authored-by: Hugo van Kemenade <1324225+hugovk@users.noreply.github.com>

Author: hugovk

.github/workflows/Brewfile

@@ -2,5 +2,5 @@ brew "gdbm"
 brew "make"
 brew "openssl@3.5"
 brew "pkg-config"
-brew "tcl-tk"
+brew "tcl-tk9"
 brew "xz"