ci: Update CI job definitions

Signed-off-by: Hiroshi Hatake <hatake@clear-code.com>

Author: cosmo0920

.travis.yml

@@ -2,7 +2,6 @@ sudo: false
 language: ruby
 
 rvm:
-  - 2.3
   - 2.4
   - 2.5.3
   - 2.6.0

appveyor.yml

@@ -5,46 +5,19 @@ version: '{build}'
 
 install:
   - SET PATH=C:\Ruby%ruby_version%\bin;%PATH%
-  - IF %ridk%==0 "%devkit%\\devkitvars.bat"
   - ruby --version
   - gem --version
-  - IF %ridk%==0 bundle install
-  - IF %ridk%==1 ridk.cmd exec bundle install
+  - ridk.cmd exec bundle install
 build: off
 test_script:
   - bundle exec rake test
 
 # https://www.appveyor.com/docs/installed-software/#ruby
 environment:
   matrix:
+    - ruby_version: "26-x64"
+    - ruby_version: "26"
     - ruby_version: "25-x64"
-      ridk: 1
     - ruby_version: "25"
-      ridk: 1
     - ruby_version: "24-x64"
-      ridk: 1
     - ruby_version: "24"
-      ridk: 1
-    - ruby_version: "23-x64"
-      devkit: C:\Ruby23-x64\DevKit
-      ridk: 0
-    - ruby_version: "23"
-      devkit: C:\Ruby23\DevKit
-      ridk: 0
-    - ruby_version: "22-x64"
-      devkit: C:\Ruby23-x64\DevKit
-      ridk: 0
-    - ruby_version: "21-x64"
-      devkit: C:\Ruby23-x64\DevKit
-      ridk: 0
-    - ruby_version: "22"
-      devkit: C:\Ruby23\DevKit
-      WIN_RAPID: true
-      ridk: 0
-    - ruby_version: "21"
-      devkit: C:\Ruby23\DevKit
-      WIN_RAPID: true
-      ridk: 0
-matrix:
-  allow_failures:
-    - ruby_version: "21"