Add ISRHandler library

[JensDMadsen]

The library provides a flexible, reusable interrupt handler class for Arduino, allowing template-based interrupt management and supporting multiple interrupts with configurable modes.

[github-actions]

A problem was found with your submission https://github.com/JensDMadsen/Multitasker

❌ ERROR: Submission URL is already in the Library Manager index.

[github-actions]

Arduino Lint has suggestions for possible improvements to https://github.com/JensDMadsen/ISRHandler:

Linting library in ISRHandler
WARNING: Unable to load the library.properties url field: 555                                                  
         See: https://arduino.github.io/arduino-cli/latest/library-specification/#libraryproperties-file-format
         (Rule LP042)                                                                                          

Linter results for project: 0 ERRORS, 1 WARNINGS

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Linting sketch in ISRHandler/examples/ISRdemo1

Linter results for project: no errors or warnings

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Linting sketch in ISRHandler/examples/ISRdemo2

Linter results for project: no errors or warnings

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

Linter results for projects: 0 ERRORS, 1 WARNINGS

[github-actions]

Thanks for your interest in contributing to the Arduino Library Manager index @JensDMadsen
Please resolve the error(s) mentioned in the previous comment.

After resolving the issue, trigger this check again by doing one of the following:

• Commit the required change to the branch you submitted this pull request from.
• Comment here, mentioning @ArduinoBot in the comment.

❗ NOTE: It is not necessary to open a new pull request. ❗

More information:
https://github.com/arduino/library-registry/blob/main/README.md#if-the-problem-is-with-the-pull-request

[github-actions]

Arduino Lint has suggestions for possible improvements to https://github.com/JensDMadsen/ISRHandler:

Linting library in ISRHandler
WARNING: Unable to load the library.properties url field: 555                                                  
         See: https://arduino.github.io/arduino-cli/latest/library-specification/#libraryproperties-file-format
         (Rule LP042)                                                                                          

Linter results for project: 0 ERRORS, 1 WARNINGS

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

Linting sketch in ISRHandler/examples/ISRdemo1

Linter results for project: no errors or warnings

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

Linting sketch in ISRHandler/examples/ISRdemo2

Linter results for project: no errors or warnings

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

Linter results for projects: 0 ERRORS, 1 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/JensDMadsen/ISRHandler/