Only run on changes in src folder

[Roald87]

With

on:
  push:
    branches:
      - master
    paths:
      - 'src/**'
      - '.github/workflows/*'
  pull_request:
    branches:
      - master
    paths:
      - 'src/**'
      - '.github/workflows/*'

it runs on every change pushed to master/pull request.

With

on:
  push:
    paths:
      - 'src/**'
      - '.github/workflows/*'
  pull_request:
    paths:
      - 'src/**'
      - '.github/workflows/*'

It runs the workflow twice. 🤷

Closing this PR without merging. Workflow will run on every push/PR then.