Fix SPI bug

[OlafFilies]

By creating this pull request you agree to the terms in CONTRIBUTING.md.
https://github.com/Infineon/.github/blob/master/CONTRIBUTING.md
--- DO NOT DELETE ANYTHING ABOVE THIS LINE ---

CONTRIBUTING.md also tells you what to expect in the PR process.
This pull request includes updates to the GitHub Actions workflows and changes to the SPICIno class in the src/spic-arduino.cpp and src/spic-arduino.hpp files. The most important changes include updating the versions of GitHub Actions used and modifying the SPICIno class to use a new SPEED constant.

GitHub Actions Updates:

• .github/workflows/build-check.yml: Updated arduino/setup-arduino-cli action from version v1.1.1 to v2.
• .github/workflows/platformio_ci.yml: Updated actions/checkout to version v4, actions/cache to version v4, and actions/setup-python to version v5.

SPICIno Class Modifications:

• src/spic-arduino.cpp: Changed the clock parameter in SPICIno constructors to use the new SPEED constant instead of ARDUINO_SPI_CLOCK. [1] [2] [3]
• src/spic-arduino.hpp: Defined a new constant SPEED with a value of 1000000.

[ederjc]

The build checks will be replaced by #2 anyway, can be merged.