Update link in travis file; remove JDK 6 setup since build won't use it

.travis.yml

@@ -5,7 +5,8 @@ language: java
   - oraclejdk11
 
 # Below this line is configuration for deploying to the Sonatype OSS repo
-# http://blog.xeiam.com/2013/05/configure-travis-ci-to-deploy-snapshots.html
+#   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 deploy --settings target/travis/settings.xml"
 
@@ -15,12 +16,6 @@ branches:
     - master
     - "2.10"
 
-# to make jdk6 work, as per: https://github.com/travis-ci/travis-ci/issues/8199
-addons:
-  apt:
-    packages:
-      - openjdk-6-jdk
-
 env:
   global:
     - secure: "YW0hrdsHvH41pb5uPJ2DGzXrBgOVT7nEyag/bAQoDcSlOQ/g55tnY6rIGkqE/aYD47IroTEhW4yLyM3tZpbrqwagX4dUX90ukjcUwUvFE1ePTSEfdBtuHVwl8f6HmLIIw2yK0dQ1gOJ21T+3g+wddvK+6sWBJJ+s3O1FePDh6X0="