Update repositories.txt

[rescenic]

Add RescenicIO library

[github-actions]

Arduino Lint has suggestions for possible improvements to https://github.com/rescenic/rescenicio:

Linting library in rescenicio
WARNING: The library.properties paragraph field repeats the sentence field. These are displayed together so redundancy  
         is not needed.                                                                                                 
         See: https://arduino.github.io/arduino-cli/latest/library-specification/#libraryproperties-file-format         
         (Rule LP036)                                                                                                   
WARNING: No example sketches found. Please provide examples.                                      
         See: https://arduino.github.io/arduino-cli/latest/library-specification/#library-examples
         (Rule LD004)                                                                             

Linter results for project: 0 ERRORS, 2 WARNINGS

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[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/rescenic/rescenicio/