Use stable Jabba script (and cache) (#56)

* Use stable Jabba script (and cache)

* Try out scala's travis template

.travis.yml

@@ -1,39 +1,39 @@
 version: ~> 1.0
+
+import: scala/scala-dev:travis/default.yml
+
 language: scala
 scala:
   - 2.13.1
 
-before_install: curl -Ls https://git.io/jabba | bash && . ~/.jabba/jabba.sh
-install: jabba install "$TRAVIS_JDK" && jabba use "$_" && java -Xmx32m -version
-
 jobs:
   include:
     - stage: check
       name: "sbt & Paradox (JDK 8)"
       script: sbt test docs/paradox
-      env: [email protected]
+      env: ADOPTOPENJDK=8
 
     - name: "sbt & Paradox (JDK 11)"
       script: sbt test docs/paradox
-      env: [email protected]
+      env: ADOPTOPENJDK=11
 
     - name: "Maven (JDK 8)"
       ## set name to "hello-world-grpc" and accept all other defaults (--force)
       script: sbt new file://$PWD --name=hello-world-grpc --force && pushd hello-world-grpc &&  mvn test         && popd || travis_terminate 1
-      env: [email protected]
+      env: ADOPTOPENJDK=8
 
     - name: "Maven (JDK 11)"
       ## set name to "hello-world-grpc" and accept all other defaults (--force)
       script: sbt new file://$PWD --name=hello-world-grpc --force && pushd hello-world-grpc &&  mvn test         && popd || travis_terminate 1
-      env: [email protected]
+      env: ADOPTOPENJDK=11
 
     - name: "Gradle (JDK 8)"
       script: sbt new file://$PWD --name=hello-world-grpc --force && pushd hello-world-grpc &&  ./gradlew --console=plain build
-      env: [email protected]
+      env: ADOPTOPENJDK=8
 
     - name: "Gradle (JDK 11)"
       script: sbt new file://$PWD --name=hello-world-grpc --force && pushd hello-world-grpc &&  ./gradlew --console=plain build
-      env: [email protected]
+      env: ADOPTOPENJDK=11
 
 stages:
   - name: check
@@ -44,10 +44,6 @@ before_cache:
 
 cache:
   directories:
-    - $HOME/.cache/coursier
-    - $HOME/.jabba/jdk
-    - $HOME/.ivy2/cache
-    - $HOME/.sbt/boot
     - $HOME/.gradle
     - $HOME/.m2/repository