Drop obsolete Travis build.
diff --git a/.travis.yml b/.travis.yml
deleted file mode 100644
index f5f56b4..0000000
--- a/.travis.yml
+++ /dev/null
@@ -1,28 +0,0 @@
-# Licensed to the Apache Software Foundation (ASF) under one or more
-# contributor license agreements. See the NOTICE file distributed with
-# this work for additional information regarding copyright ownership.
-# The ASF licenses this file to You under the Apache License, Version 2.0
-# (the "License"); you may not use this file except in compliance with
-# the License. You may obtain a copy of the License at
-#
-# http://www.apache.org/licenses/LICENSE-2.0
-#
-# Unless required by applicable law or agreed to in writing, software
-# distributed under the License is distributed on an "AS IS" BASIS,
-# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-# See the License for the specific language governing permissions and
-# limitations under the License.
-
-language: java
-
-jdk:
- - openjdk8
- - openjdk11
- - openjdk16
- - openjdk-ea
-
-script:
- - mvn -V --no-transfer-progress
-
-after_success:
- - mvn clean test jacoco:report coveralls:report -Ptravis-jacoco --no-transfer-progress
