fix build for Python versions <3.9

[fominykhandrei]

What's new

• Fix the following build issue on Ubuntu 20.04:

  File "./scripts/meta.py", line 52, in merge
    full |= dict
TypeError: unsupported operand type(s) for |=: 'dict' and 'dict'
make: *** [Makefile:17: all] Error 1

The merge (|) and update (|=) operators for dictionaries were introduced in Python 3.9 so they do not work in older versions. Use an equivalent

Verification

• Compile

Checklist (do not modify)

• PR has description of feature/bug or link to Confluence/Jira task
• Description contains actions to verify feature/bugfix
• I've built this code, uploaded it to the device and verified feature/bugfix

[aprosvetova]

lgtm