Travis is not used any longer

.travis.yml

@@ -1,50 +0,0 @@
-language: cpp
-
-dist: bionic
-
-compiler:
-- gcc
-
-os:
-- linux
-
-branches:
-    only:
-    - master
-
-notifications:
-    email: false
-
-before_install:
-- sudo apt-get update -qq
-
-install:
-- sudo apt list -a cmake
-- sudo apt-get install cmake
-  # first we create a directory for the CMake binaries
-- DEPS_DIR="${TRAVIS_BUILD_DIR}/deps"
-- mkdir ${DEPS_DIR} && cd ${DEPS_DIR}
-# we use wget to fetch the cmake binaries
-- travis_retry wget --no-check-certificate https://cmake.org/files/v3.18/cmake-3.18.6-Linux-x86_64.tar.gz
-# this is optional, but useful:
-# do a quick md5 check to ensure that the archive we downloaded did not get compromised
-#- echo "4d9a9d3351161073a67e49366d701b6fa4b0343781982dc5eef08a02a750d403 *cmake-3.18.0-Linux-x86_64.tar.gz" > cmake_md5.txt
-#- md5sum -c cmake_md5.txt
-# extract the binaries; the output here is quite lengthy,
-# so we swallow it to not clutter up the travis console
-- tar -xvf cmake-3.18.6-Linux-x86_64.tar.gz > /dev/null
-- mv cmake-3.18.6-Linux-x86_64 cmake-install
-# add both the top-level directory and the bin directory from the archive
-# to the system PATH. By adding it to the front of the path we hide the
-# preinstalled CMake with our own.
-- PATH=${DEPS_DIR}/cmake-install:${DEPS_DIR}/cmake-install/bin:$PATH
-# don't forget to switch back to the main build directory once you are done
-- cd ${TRAVIS_BUILD_DIR}
-
-script:
-- mkdir build
-- cmake -B build -S . -DCMAKE_BUILD_TYPE=Release -DELFIO_BUILD_EXAMPLES=YES -DELFIO_BUILD_TESTS=YES
-- cmake --build build --config Release
-- cd build
-- ctest -VV
-- cd ..