Remove obsolete .travis.yml (#410)

As this hasn't been edited in 8 years, and the badge to travis 404s, I'm
guessing that this is obsolete. It was a little distracting when I was
trying to figure out how you run your tests (not on GitHub Actions, so I
wondered briefly if it was on Travis).

.travis.yml

diff --git a/.travis.yml b/.travis.yml
deleted file mode 100644
index 4721a07..0000000
--- a/.travis.yml
+++ /dev/null
@@ -1,15 +0,0 @@
-language: cpp
-os:
- - linux
- - osx
-before_script:
- - mkdir build
- - cd build
-script:
- - cmake ..
- - make
- - ./cpuid-dump
- - ./isa-info
- - ./cpu-info
- - ./cache-info
- - ctest --verbose