Stop testing with Rubies older than 2.7 on Windows

Author: ashmaroli

appveyor.yml

@@ -1,5 +1,7 @@
 version: "{build}"
 
+image: Visual Studio 2019
+
 clone_depth: 5
 
 branches:
@@ -13,22 +15,22 @@ build: off
 environment:
   BUNDLE_WITHOUT: "benchmark:development"
   matrix:
-    - RUBY_FOLDER_VER: "26"
+    - RUBY_FOLDER_VER: "27"
       TZINFO_VERSION: "~> 1.2"
       TEST_SUITE: "test"
-    - RUBY_FOLDER_VER: "26"
+    - RUBY_FOLDER_VER: "27"
       TZINFO_VERSION: "~> 2.0"
       TEST_SUITE: "test"
-    - RUBY_FOLDER_VER: "26"
+    - RUBY_FOLDER_VER: "27"
       TEST_SUITE: "default-site"
-    - RUBY_FOLDER_VER: "26"
+    - RUBY_FOLDER_VER: "27"
       TEST_SUITE: "profile-docs"
-    - RUBY_FOLDER_VER: "26"
+    - RUBY_FOLDER_VER: "27"
       TEST_SUITE: "memprof"
-    - RUBY_FOLDER_VER: "26"
+    - RUBY_FOLDER_VER: "27"
       TZINFO_VERSION: "~> 1.2"
       TEST_SUITE: "cucumber"
-    - RUBY_FOLDER_VER: "26"
+    - RUBY_FOLDER_VER: "27"
       TZINFO_VERSION: "~> 2.0"
       TEST_SUITE: "cucumber"