Port `squarelinestudio_lvgl_v8.ino` to LVGLv9

[aliphys]

Issue #27 describes the squarelinestudio_lvgl_v8.ino sketch not compiling with latest libraries due to (current) lack of LVGLv9 support.

As clarified by @per1234 :

However, it should be noted that SquareLine Studio have stated they do plan to provide LVGL 9.x support:
https://forum.squareline.io/t/q-plans-timeline-for-lvgl-9-observer-support/2782/2

Therefore:

• squarelinestudio_lvgl_v8.ino will remain in the library as is and is labelled as having LVGLv8 support only both from the filename and the compiler directives

  Arduino_GigaDisplay/examples/lvgl/squarelinestudio_lvgl_v8/squarelinestudio_lvgl_v8.ino

  Lines 32 to 34 in de47486

  	#if (LVGL_VERSION_MAJOR >= 9)
  	#error "SquareLine Studio has ended its collaboration with LVGL. It only supports LVGL version 8 and earlier."
  	#endif

• When/if LVGLv9 support is provided by SquareLine (ETA is April), then the example can be modified as needed and this issue is closed.

[aliphys]

Enquired about status of LVGLv9 support from Squareline Studio (thanks Sofi):

our new version release is out just as per yesterday with LVGL 9.1 support.

Enjoy your work with Arduino and our tool!

Version 1.4.1 changelog states that there is LVGLV9 support 🎉

[aliphys]

@per1234 could you remove the BLOCKED label?

[aliphys]

Realized that SquareLine Studio version 1.4.1 does not - as of now - support the required pathway for exporting the files. According to Square Studio, this functionality should be present in the next release.

Version 1.4.1 - LVGL 8.3

Version 1.4.1 - LVGL 9.1

[aliphys]

SquareLine Studio 1.4.1 now provides Arduino export for LVGL9.1