Github workflow adjustments

[edeltoaster]

Description

Optimization of Github workflows:

• taken care about deprecated actions and actions that may not work anymore with Node 24
• used hashes to reference actions to diminish the risk of supply-chain attacks
• fixed permissions
• added caching for dependencies

PR Checklist

• Did you format your code using format.bash?
• Does the VST3 plugin pass all of the unit tests in the VST3PluginTestHost? (Download it as part of the VST3 SDK here.)
  • Windows
  • macOS
• Does your PR add, remove, or rename any plugin parameters? If yes...
  • Have you ensured that the plug-in unserializes correctly?
  • Have you ensured that older versions of the plug-in load correctly? (See Unserialization.cpp.)
• Does your PR add or remove any graphical assets? If yes, are they defined in config.h and added in the two required locations in main.rc?