ci: remove Travis CI

We are are moving to Gitlab CI.
Signed-off-by: Filipe Laíns <lains@archlinux.org>
Signed-off-by: Lukas Fleischer <lfleischer@archlinux.org>

.travis.yml

-language: python
-
-python: 3.6
-
-addons:
-    apt:
-        packages:
-        - bsdtar
-        - libarchive-dev
-        - libgpgme11-dev
-        - libprotobuf-dev
-
-install:
-    - curl https://codeload.github.com/libgit2/libgit2/tar.gz/v0.26.0 | tar -xz
-    - curl https://sources.archlinux.org/other/pacman/pacman-5.0.2.tar.gz | tar -xz
-    - curl https://git.archlinux.org/pyalpm.git/snapshot/pyalpm-0.8.1.tar.gz | tar -xz
-    - ( cd libgit2-0.26.0 && cmake -DCMAKE_BUILD_TYPE=Release -DCMAKE_INSTALL_PREFIX=/usr && make && sudo make install )
-    - ( cd pacman-5.0.2 && ./configure --prefix=/usr && make && sudo make install )
-    - ( cd pyalpm-0.8.1 && python setup.py build && python setup.py install )
-    - pip install mysql-connector-python-rf pygit2==0.26 srcinfo
-    - pip install bleach Markdown
-
-script: make -C test