Fix cache key inconsistency and typo in 'Compile examples' GitHub Actions workflow

[anilrajrimal1]

Changes:

• Aligned cache keys for esp8266 and esp32 jobs to use ${{ github.ref }} in the key, improving cache consistency across branches.
• Fixed a typo in the Install 3rd party dependencies step (dependecies → dependencies).

These changes ensure more efficient caching and fix a minor issue in the workflow.