Travis CI: switch to xenial, cache Maven, proper SonarQube secret

Author: cardil

.travis.yml

@@ -1,6 +1,6 @@
 language: java
 sudo: false
-dist: trusty
+dist: xenial
 install: ./mvnw package -DskipTests=true -Dmaven.javadoc.skip=true -B -V
 script: ./mvnw verify --fail-at-end -U -V
 notifications:
@@ -15,19 +15,22 @@ git:
 matrix:
   include:
     # Quality testing
-    - jdk: oraclejdk8
+    - jdk: openjdk8
       env: JACOCO=true RELEASE_CHECKS=true
-    - jdk: oraclejdk8
+    - jdk: openjdk8
       env: JACOCO=true SONAR=publish
     # Performance testing
     - jdk: openjdk8
       env: JACOCO=false
-    - jdk: oraclejdk9
-      env: JACOCO=false
-    - jdk: oraclejdk11
+    - jdk: openjdk11
       env: JACOCO=false
 addons:
   sonarcloud:
     organization: wavesoftware
     token:
-      secure: "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"
+      secure: "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"
+before_cache:
+  - rm -fr $HOME/.m2/repository
+cache:
+  directories:
+    - $HOME/.m2/repository