message: Add python3 dep to freebsd install instructions
diff: @@ -148,7 +148,7 @@ command that should install all of them. If something is still found to be
  missing, please open an issue.
  ```sh
  -pkg install cmake freetype2 fontconfig pkgconf
  +pkg install cmake freetype2 fontconfig pkgconf python3
  ```
  #### OpenBSD
  