remove travis config

TravisCI is no longer free starting January 2021.
We will use Github Actions instead.

.travis.yml

@@ -1,33 +0,0 @@
-dist: trusty
-sudo: false
-language: java
-env:
-  global:
-    - export PATH="$PATH:$HOME/bin"
-    - export LD_LIBRARY_PATH="$LD_LIBRARY_PATH:$HOME/lib"
-    - export PKG_CONFIG_PATH="$HOME/lib/pkgconfig"
-addons:
-  apt:
-    sources:
-      - ubuntu-toolchain-r-test
-    packages:
-      - gcc-7
-      - g++-7
-
-install:
-  - curl -O https://capnproto.org/capnproto-c++-0.7.0.tar.gz
-  - tar zxf capnproto-c++-0.7.0.tar.gz
-  - cd capnproto-c++-0.7.0
-  - ./configure --prefix=$HOME CC=gcc-7 CXX=g++-7
-  - make -j3
-  - make install
-  - cd ../
-
-jdk:
-  - oraclejdk8
-  - openjdk8
-script:
-  - make CC=gcc-7 CXX=g++-7
-  - mvn compile
-  - mvn test
-

README.md

@@ -1,6 +1,6 @@
 # capnproto-java: Cap'n Proto for Java
 
-[![Build Status](https://travis-ci.org/capnproto/capnproto-java.svg?branch=master)](https://travis-ci.org/capnproto/capnproto-java)
+[![Build Status](https://github.com/capnproto/capnproto-java/workflows/CI/badge.svg?branch=master&event=push)](https://github.com/capnproto/capnproto-java/actions?query=workflow%3ACI)
 
 [Cap'n Proto](http://capnproto.org) is an extremely efficient protocol for sharing data
 and capabilities, and capnproto-java is a pure Java implementation.