Remove support for ruby 2.5.

This includes deleting all of the associated tests.

PiperOrigin-RevId: 498228866

kokoro/linux/ruby25/common.cfg

@@ -1,26 +0,0 @@
-# Config file for running tests in Kokoro
-
-# Location of the build script in repository
-build_file: "protobuf/kokoro/linux/bazel.sh"
-timeout_mins: 120
-
-env_vars {
-  key: "CONTAINER_IMAGE"
-  value: "gcr.io/protobuf-build/ruby/linux:ruby-2.5.1-64e8944e4f18d7d6c9649112a8a93be57e693cd8"
-}
-
-env_vars {
-  key: "BAZEL_TARGETS"
-  value: "//ruby/..."
-}
-
-env_vars {
-  key: "BAZEL_EXTRA_FLAGS"
-  value: "--define=ruby_platform=c"
-}
-
-action {
-  define_artifacts {
-    regex: "**/sponge_log.*"
-  }
-}

kokoro/linux/ruby25/continuous.cfg

@@ -1 +0,0 @@
-# Keep this file empty! Use common.cfg instead.

kokoro/linux/ruby25/presubmit.cfg

@@ -1 +0,0 @@
-# Keep this file empty! Use common.cfg instead.

kokoro/macos/ruby25/build.sh

@@ -1,13 +0,0 @@
-#!/bin/bash
-#
-# Build file to set up and run tests
-
-# Change to repo root
-cd $(dirname $0)/../../..
-
-# Prepare worker environment to run tests
-KOKORO_INSTALL_RVM=yes
-source kokoro/macos/prepare_build_macos_rc
-
-cd ruby
-./travis-test.sh ruby-2.5.1

kokoro/macos/ruby25/common.cfg

@@ -1,27 +0,0 @@
-# Config file for running tests in Kokoro
-
-# Location of the build script in repository
-build_file: "protobuf/kokoro/macos/ruby25/build.sh"
-timeout_mins: 1440
-
-before_action {
-  fetch_keystore {
-    keystore_resource {
-      keystore_config_id: 77103
-      keyname: "kokoro_gcp_service"
-    }
-  }
-}
-bazel_setting {
-  project_id: "protobuf-build"
-  bes_backend_address: "buildeventservice.googleapis.com"
-  foundry_backend_address: "remotebuildexecution.googleapis.com"
-  upsalite_frontend_address: "https://source.cloud.google.com"
-  local_execution: true
-
-  # Need to be same as the fetch_keystore entry in the previous step.
-  auth_credential: {
-    keystore_config_id: 77103
-    keyname: "kokoro_gcp_service"
-  }
-}

kokoro/macos/ruby25/continuous.cfg

@@ -1 +0,0 @@
-# Keep this file empty! Use common.cfg instead.

kokoro/macos/ruby25/presubmit.cfg

@@ -1 +0,0 @@
-# Keep this file empty! Use common.cfg instead.

kokoro/release/ruby/macos/ruby/ruby_build_environment.sh

@@ -14,8 +14,8 @@ sudo chown -R $(whoami) /Library/Ruby/
 
 source $HOME/.rvm/scripts/rvm
 set -e  # rvm commands are very verbose
-time rvm install 2.5.0
-rvm use 2.5.0
+time rvm install 2.6.0
+rvm use 2.6.0
 gem install rake-compiler --no-document
 gem install bundler --no-document
 time rvm install 3.1.0
@@ -106,10 +106,10 @@ for v in 3.0.0 2.7.0 ; do
   # rake -f "$CROSS_RUBY" cross-ruby VERSION="$v" HOST=aarch64-darwin MAKE="$MAKE"
 done
 set +x
-rvm use 2.5.0
+rvm use 2.6.0
 set -x
-ruby --version | grep 'ruby 2.5.0'
-for v in 2.6.0 2.5.1; do
+ruby --version | grep 'ruby 2.6.0'
+for v in 2.6.0 ; do
   ccache -c
   rake -f "$CROSS_RUBY" cross-ruby VERSION="$v" HOST=x86_64-darwin MAKE="$MAKE"
   # Disabled until it can be fixed: https://github.com/protocolbuffers/protobuf/issues/9804

ruby/Rakefile

@@ -133,7 +133,7 @@ else
     ['x86-mingw32', 'x64-mingw32', 'x64-mingw-ucrt', 'x86_64-linux', 'x86-linux'].each do |plat|
       RakeCompilerDock.sh <<-"EOT", platform: plat
         bundle && \
-        IN_DOCKER=true rake native:#{plat} pkg/#{spec.full_name}-#{plat}.gem RUBY_CC_VERSION=3.1.0:3.0.0:2.7.0:2.6.0:2.5.0
+        IN_DOCKER=true rake native:#{plat} pkg/#{spec.full_name}-#{plat}.gem RUBY_CC_VERSION=3.1.0:3.0.0:2.7.0:2.6.0
       EOT
     end
   end
@@ -141,7 +141,7 @@ else
   if RUBY_PLATFORM =~ /darwin/
     task 'gem:native' do
       system "rake genproto"
-      system "rake cross native gem RUBY_CC_VERSION=3.1.0:3.0.0:2.7.0:2.6.0:2.5.1"
+      system "rake cross native gem RUBY_CC_VERSION=3.1.0:3.0.0:2.7.0:2.6.0"
     end
   else
     task 'gem:native' => [:genproto, 'gem:windows', 'gem:java']