Fixing CI/CD

[mofosyne]

Did an investigation in #243 and traced the issue to AppVeyor dropping support for QT v6.1

As shown in https://www.appveyor.com/docs/windows-images-software/

I made a smaller PR to just change the version to latest QT so it can be merged now

#244

This will hopefully unblock the testing of other PR like mine #241

[thiagomacieira]

I also need to rewrite the non-Windows one to use GitHub Actions, but as usual.... lack of time.

[mofosyne]

Ah that's fair enough. Not sure about how travis CI works, but i got an AI to take a stab at translating it to github actions.

https://github.com/intel/tinycbor/8b3e97d60eae572d56bac24a1c33444e0436c7a4/.travis.yml

After quite a few rounds of prompting using above as reference... it gave below which looks correct
No assurance of correctness, but should make things easier.

Here's the generated .github/workflows/main.yml

name: CI
on:
  push:
    branches: [main]
  pull_request:

jobs:

  build:

    runs-on: ubuntu-latest

    strategy:
      matrix:
        include:
        
          - qt-version: 5.12.1
            os: linux
            dist: xenial 
            cc: gcc
            cxx: g++
            env:
              CFLAGS: "-Os -march=native"
              LDFLAGS: "-Wl,--no-undefined -lm"

          - qt-version: 5.12.1 
            os: linux
            dist: xenial
            cc: clang
            cxx: clang++
            env:
              CFLAGS: "-Oz"
              LDFLAGS: "-Wl,--no-undefined -lm"
              MAKEFLAGS: -s

          # Add other builds from matrix
            
    steps:
    
    - uses: actions/checkout@v2

    - name: Install Qt
      uses: jurplel/install-qt-action@v2
      with:
        version: ${{ matrix.qt-version }}
       
    - name: Install apt packages  
      run: |
        sudo apt-get update
        sudo apt-get install -y qt512base valgrind doxygen

    - name: Configure
      run: |
        eval "${{ matrix.cc }} && ${{ matrix.cxx }}"
        make -f Makefile.configure configure

    - name: Build
      env:
        CFLAGS: "${{ matrix.env.CFLAGS }}"
      run: |
        make lib/libtinycbor.a

    - name: Check size
      run: |
        size lib/libtinycbor.a

    - name: Clean
      run: |
        make -s clean

    - name: Build debug
      env:
        CFLAGS: "-O0 -g"
      run: |
        make lib/libtinycbor.a

    - name: Tests
      env:
        LDFLAGS: "${{ matrix.env.LDFLAGS }}"
        LDLIBS: "${{ matrix.env.LDLIBS }}"  
      run: |
        grep -q freestanding-pass .config || make tests/Makefile
        grep -q freestanding-pass .config || (cd tests && make check)

    - name: Clean
      run: |
        make -s clean
        
  docs:

    runs-on: ubuntu-latest
    if: github.ref == 'refs/heads/main'

    steps:
    
    - uses: actions/checkout@v2

    - name: Build docs
      run: ./scripts/update-docs.sh

[thiagomacieira]

@pjonsson is working on this on #247. Would you be able to lend a hand?