Switch from travis-ci to Github Actions for CI

This drops the travis-ci config and adds config for running tests
via tox in Github Actions. It also updates the list of envs in
tox.ini for recent Python 3 versions.

Signed-off-by: Adam Williamson <awilliam@redhat.com>

.github/dependabot.yml

+---
+version: 2
+updates:
+  - package-ecosystem: "github-actions"
+    directory: "/"
+    schedule:
+      interval: "daily"

.github/workflows/tox.yml

+---
+name: Test Python package with Tox
+
+on: [pull_request]
+
+jobs:
+  build:
+    runs-on: ${{ matrix.os }}
+    strategy:
+      max-parallel: 4
+      fail-fast: false
+      matrix:
+        python-version:
+          - "3.6"
+          - "3.7"
+          - "3.8"
+          - "3.9"
+          - "3.10"
+          - "3.11"
+          - "3.12.0-alpha - 3.12.0"
+        include:
+          - os: "ubuntu-latest"
+          - os: "ubuntu-20.04"
+            python-version: "3.6"
+
+    steps:
+      - uses: actions/checkout@v3
+        with:
+          fetch-depth: 0
+      - name: Set up Python ${{ matrix.python-version }}
+        uses: actions/setup-python@v4.5.0
+        with:
+          python-version: ${{ matrix.python-version }}
+      - name: Install dependencies
+        run: |
+          python -m pip install --upgrade pip
+          pip install tox tox-gh-actions
+      - name: Test with tox
+        run: tox

.travis.yml

-language: python
-python:
-- 2.7
-- 3.5
-- 3.6
-- 3.7
-- 3.8
-install:
-- python setup.py install
-- pip install coveralls flake8
-script:
-- python setup.py test
-- flake8 mwclient
-after_success:
-- coveralls
-deploy:
-  provider: pypi
-  user: danmichaelo
-  password:
-    secure: iRaoF9UNIIzwNR2SP60zL7Ub33lgCTYddk4JkpfNNjz/olZaUEGTbrpttq1wQ9thzwYBgp6PbwspgEdIQWOgDLlT75XowkeLpp7UzRNwKjf7gUVaMJuAYtmhbofaWZFGft3zSbsDEt19z8mqepQXSUUN7dcfH4QVUvishElQT5k=
-  distributions: "sdist bdist_wheel"
-  on:
-    tags: true
-    repo: mwclient/mwclient
-    python: '3.8'

tox.ini

 [tox]
-envlist = py27,py35,py36,py37,py38,flake
+envlist = py27,py35,py36,py37,py38,py39,py310,py311,py312,flake
 
 [testenv]
 deps =