ci: unbreak pip on ubuntu 24.04

Signed-off-by: Daniil Tatianin <99danilt@gmail.com>

.github/workflows/main.yml

@@ -15,6 +15,7 @@ jobs:
         run: |
           sudo apt update
           sudo apt install python3 python3-pip
+          export PIP_BREAK_SYSTEM_PACKAGES=1
           pip install flake8 mypy
 
       - name: Run flake8 on the project