Create the github workflow for functional tests

.github/workflows/main.yml

+name: functional test
+
+on:
+  push:
+    branches: [ master ]
+  pull_request:
+    branches: [ master ]
+
+jobs:
+  check_all_configs:
+
+    runs-on: ubuntu-latest
+
+    strategy:
+      max-parallel: 4
+      fail-fast: false
+      matrix:
+        python-version: [3.6, 3.7, 3.8]
+        # github runner with python 3.5 currently fails to install this package
+
+    steps:
+
+    - uses: actions/checkout@v2
+
+    - name: Set up Python ${{ matrix.python-version }}
+      uses: actions/setup-python@v1
+      with:
+        python-version: ${{ matrix.python-version }}
+
+    - name: Install
+      run: |
+        python -m pip install --upgrade pip
+        pip install setuptools
+        python ./setup.py install
+
+    - name: Try
+      run: |
+        set -x
+        kconfig-hardened-check
+        echo $?
+

README.md

 # kconfig-hardened-check
 
+![functional test](https://github.com/a13xp0p0v/kconfig-hardened-check/workflows/functional%20test/badge.svg)
+
 ## Motivation
 
 There are plenty of Linux kernel hardening config options. A lot of them are