Update repositories.txt

[flybrianfly]

No description provided.

[github-actions]

Arduino Lint has suggestions for possible improvements to https://github.com/bolderflight/excitation:

Linting library in excitation
INFO: No header file found matching library name (Bolder_Flight_Systems_Excitation.h). Best practices are for primary   
      header filename to match library name. (Rule LS008)                                                               
WARNING: library.properties name value Bolder Flight Systems Excitation is longer than the recommended length of 16     
         characters. (Rule LP010)                                                                                       
WARNING: library.properties name Bolder Flight Systems Excitation contains spaces. Although supported, best practices is
         to not use spaces. (Rule LP015)                                                                                
WARNING: library.properties depends field item(s) Bolder Flight Systems Units not found in the Library Manager index.   
         (Rule LP048)                                                                                                   

Linter results for project: 0 ERRORS, 3 WARNINGS

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

Linting sketch in excitation/examples/arduino/excitation_example

Linter results for project: no errors or warnings

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

Linter results for projects: 0 ERRORS, 3 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/bolderflight/excitation/