also try to improve travis settings

Author: cowtowncoder

.travis.yml

@@ -1,9 +1,24 @@
 language: java
 
+git:
+  quiet: true
+  submodules: false
+
 jdk:
   - openjdk8
   - openjdk11
 
+# 2019-11-26, tatu: Let's try caching Maven dependencies
+cache:
+  directories:
+    - $HOME/.m2
+
+# Below this line is configuration for deploying to the Sonatype OSS repo
+# https://knowm.org/configure-travis-ci-to-deploy-snapshots/
+before_install: "git clone -b travis `git config --get remote.origin.url` target/travis"
+after_success:
+  - "mvn -B source:jar javadoc:jar deploy --settings target/travis/settings.xml"
+
 # whitelist
 branches:
   only: