Update default Ruby version to 2.6.1 (#171)

Author: dazuma

Rakefile

@@ -17,12 +17,12 @@
 RUNTIME_PROJECT="gcp-runtimes"
 BUNDLER1_VERSION="1.17.3"
 BUNDLER2_VERSION="2.0.1"
-DEFAULT_RUBY_VERSION="2.3.8"
-NODEJS_VERSION="10.15.1"
-GCLOUD_VERSION="232.0.0"
+DEFAULT_RUBY_VERSION="2.6.1"
+NODEJS_VERSION="10.15.2"
+GCLOUD_VERSION="237.0.0"
 OS_NAME="ubuntu16"
 
-LOCAL_PREBUILT_RUBY_VERSIONS=["2.3.8", "2.4.5", "2.5.3", "2.6.0"]
+LOCAL_PREBUILT_RUBY_VERSIONS=["2.4.5", "2.5.3", "2.6.1"]
 LOCAL_PREBUILT_RUBY_IMAGE_BASE="ruby-prebuilt-"
 LOCAL_PREBUILT_RUBY_IMAGE_TAG="latest"
 RELEASED_PREBUILT_RUBY_VERSIONS=::File.readlines("ruby-pipeline/ruby-latest.yaml")

build-ruby-runtime-images.sh

@@ -18,12 +18,12 @@
 # This is the Ruby version that is installed in the "basic" convenience image
 # and that is used to run generate-dockerfile. It is NOT the same as the Ruby
 # version used by the runtime by default if one is not specified by the app.
-BASIC_RUBY_VERSION=2.3.8
+BASIC_RUBY_VERSION=2.6.1
 
 BUNDLER1_VERSION=1.17.3
 BUNDLER2_VERSION=2.0.1
-NODEJS_VERSION=10.15.1
-GCLOUD_VERSION=232.0.0
+NODEJS_VERSION=10.15.2
+GCLOUD_VERSION=237.0.0
 
 
 set -e

ruby-pipeline/ruby-latest.yaml

@@ -44,7 +44,7 @@ steps:
            '--prebuilt-image=2.5.3=gcr.io/gcp-runtimes/ruby/ubuntu16/prebuilt/ruby-2.5.3:latest',
            '--prebuilt-image=2.6.0=gcr.io/gcp-runtimes/ruby/ubuntu16/prebuilt/ruby-2.6.0:latest',
            '--prebuilt-image=2.6.1=gcr.io/gcp-runtimes/ruby/ubuntu16/prebuilt/ruby-2.6.1:latest',
-           '--default-ruby-version=2.3.8']
+           '--default-ruby-version=2.6.1']
   - name: 'gcr.io/cloud-builders/docker:latest'
     args: ['build', '--network=cloudbuild', '-t', '$_OUTPUT_IMAGE', '.']
 images: