remove Travis-CI - going to switch to github actions

.travis.yml

@@ -1,14 +0,0 @@
-language: rust
-before_script: sccache --version || cargo install sccache
-script: RUSTC_WRAPPER=sccache cargo run
-
-env:
-  global:
-    - RUST_LOG=warn
-    - SCCACHE_CACHE_SIZE=1G
-
-cache:
-  directories:
-    - ~/.cargo/bin
-    - ~/.cache/sccache
-    - results # So we don't have to check all the things every time