drop Travis CI

All tests were moved to schutzbot, there's no need to run them on Travis.

.travis.yml

@@ -1,26 +0,0 @@
-dist: bionic
-addons:
-  apt:
-    packages:
-      - genisoimage
-      - gnupg2
-      - qemu-utils
-      - qemu-kvm
-      - rpm
-      - systemd-container
-matrix:
-  include:
-    - name: fedora_31
-      arch: amd64
-    - name: fedora_32
-      arch: amd64
-
-language: generic
-script:
-  # set go version to 1.12.x
-  - eval "$(gimme 1.12.x)"
-  # ubuntu's rpm package sets dbpath to ~/.rpmdb, which makes rpm fail...
-  - sudo sh -c 'mkdir /etc/rpm; echo "%_dbpath /var/lib/rpm" > /etc/rpm/macros'
-  - export GO111MODULE=on
-  - go test -c -tags 'travis integration' -o osbuild-image-tests ./cmd/osbuild-image-tests
-  - sudo ./osbuild-image-tests -test.v test/cases/${TRAVIS_JOB_NAME}*-x86_64-vhd-boot.json