add Simple Modbus Slave

[kolod]

Arduino Simple Modbus Slave is an ISC licensed library to handle Modbus requests on Arduino (slave).

Features

To keep it simple and to reduce memory consumption, only the two following
Modbus functions are supported:

• read holding registers (0x03)
• write multiple registers (0x10)****

[github-actions]

❌ ERROR: Arduino Lint found errors with https://github.com/kolod/SevenSegmentTM1637:

Linting library in SevenSegmentTM1637
ERROR: Library name SevenSegmentTM1637 is in use by a library in the Library Manager index. Each library must have a    
       unique name value. If your library is already in the index, use the "--library-manager update" flag.             
       See: https://arduino.github.io/arduino-cli/latest/library-specification/#libraryproperties-file-format           
       (Rule LP017)                                                                                                     

Linter results for project: 1 ERRORS, 0 WARNINGS

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Linting sketch in SevenSegmentTM1637/examples/Basic

Linter results for project: no errors or warnings

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Linting sketch in SevenSegmentTM1637/examples/ExtClock

Linter results for project: no errors or warnings

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Linting sketch in SevenSegmentTM1637/examples/ExtScoreboard

Linter results for project: no errors or warnings

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Linting sketch in SevenSegmentTM1637/examples/FunPrintAll

Linter results for project: no errors or warnings

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Linting sketch in SevenSegmentTM1637/examples/FunPrintLevel

Linter results for project: no errors or warnings

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Linting sketch in SevenSegmentTM1637/examples/LowLevel

Linter results for project: no errors or warnings

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Linting sketch in SevenSegmentTM1637/examples/PrintNumber

Linter results for project: no errors or warnings

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Linting sketch in SevenSegmentTM1637/examples/SerialPrint

Linter results for project: no errors or warnings

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Linter results for projects: 1 ERRORS, 0 WARNINGS

[github-actions]

Thanks for your interest in contributing to the Arduino Library Manager index @kolod
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