Update repositories.txt

[geekfactory]

Add GFDisplay7S library from Geek Factory

[github-actions]

Arduino Lint has suggestions for possible improvements to https://github.com/geekfactory/GFDisplay7S:

Linting library in GFDisplay7S
INFO: No header file found matching library name (Geek_Factory_GFDisplay7S_Library.h). Best practices are for primary   
      header filename to match library name.                                                                            
      See: https://arduino.github.io/arduino-cli/latest/library-specification/#libraryproperties-file-format            
      (Rule LS008)                                                                                                      
WARNING: library.properties name Geek Factory GFDisplay7S Library contains spaces. Although supported, best practices is
         to not use spaces.                                                                                             
         See: https://arduino.github.io/arduino-cli/latest/library-specification/#libraryproperties-file-format         
         (Rule LP015)                                                                                                   
WARNING: Library name Geek Factory GFDisplay7S Library contains "library". This is superfluous.                
         See: https://arduino.github.io/arduino-cli/latest/library-specification/#libraryproperties-file-format
         (Rule LP016)                                                                                          

Linter results for project: 0 ERRORS, 2 WARNINGS

-------------------

Linting sketch in GFDisplay7S/examples/GFDisplay7S-interrupt

Linter results for project: no errors or warnings

-------------------

Linting sketch in GFDisplay7S/examples/GFDisplay7S-simple

Linter results for project: no errors or warnings

-------------------

Linter results for projects: 0 ERRORS, 2 WARNINGS

[github-actions]

Your submission has now been accepted! Thanks for your contribution to the Arduino Library Manager index.

The library(s) will be available for installation via Library Manager within a day's time.

You can check the logs from the Library Manager indexer for your library(s) here:
http://downloads.arduino.cc/libraries/logs/github.com/geekfactory/GFDisplay7S/