chore: drop Ruby 2.1 support (EOL), update CircleCI config

.editorconfig

@@ -10,4 +10,4 @@ trim_trailing_whitespace = true
 insert_final_newline = true
 
 [*.md]
-trim_trailing_whitespace = true
+trim_trailing_whitespace = false

.travis.yml

@@ -1,6 +1,5 @@
 language: ruby
 rvm:
-  - 2.1.10
   - 2.2.7
   - 2.3.4
   - 2.4.1

README.md

@@ -73,8 +73,8 @@ bundle install --without development
 ```shell
 ./mp3lyrics.rb <dir> [-override true/false] [-use lyricwikia/genius/metrolyrics/azlyrics/swiftlyrics]
 ```
-**dir** is the folder with your music, it's iterated recursively.
-**override** is a boolean toggle to override existing lyrics (defaults to *false*).
+**dir** is the folder with your music, it's iterated recursively.  
+**override** is a boolean toggle to override existing lyrics (defaults to *false*).  
 **use** is a specific wiki to be used to download lyrics (all wikis are used by default).
 
 ## Tests

appveyor.yml

@@ -20,8 +20,6 @@ test_script:
 
 environment:
   matrix:
-    - ruby_version: "21"
-    - ruby_version: "21-x64"
     - ruby_version: "22"
     - ruby_version: "22-x64"
     - ruby_version: "23"

circle.yml

@@ -6,16 +6,6 @@ machine:
     - >
       case $CIRCLE_NODE_INDEX in
         0)
-          if [[ -e ~/rvm_binaries/ruby-2.1.10.tar.bz2 ]]
-          then
-            rvm mount ~/rvm_binaries/ruby-2.1.10.tar.bz2
-          else
-            mkdir -p ~/rvm_binaries
-            rvm install 2.1.10
-            cd ~/rvm_binaries && rvm prepare 2.1.10
-          fi
-          ;;
-        1)
           if [[ -e ~/rvm_binaries/ruby-2.2.7.tar.bz2 ]]
           then
             rvm mount ~/rvm_binaries/ruby-2.2.7.tar.bz2
@@ -25,7 +15,7 @@ machine:
             cd ~/rvm_binaries && rvm prepare 2.2.7
           fi
           ;;
-        2)
+        1)
           if [[ -e ~/rvm_binaries/ruby-2.3.4.tar.bz2 ]]
           then
             rvm mount ~/rvm_binaries/ruby-2.3.4.tar.bz2
@@ -35,7 +25,7 @@ machine:
             cd ~/rvm_binaries && rvm prepare 2.3.4
           fi
           ;;
-        3)
+        2)
           if [[ -e ~/rvm_binaries/ruby-2.4.1.tar.bz2 ]]
           then
             rvm mount ~/rvm_binaries/ruby-2.4.1.tar.bz2
@@ -48,8 +38,6 @@ machine:
       esac
 
 dependencies:
-  bundler:
-    without: [test]
   cache_directories:
     - ~/rvm_binaries
     - vendor/bundle
@@ -58,20 +46,17 @@ dependencies:
     - >
       case $CIRCLE_NODE_INDEX in
        0)
-         rvm-exec 2.1.10 bash -c "bundle check --path=vendor/bundle || bundle install --path=vendor/bundle"
-         ;;
-       1)
          rvm-exec 2.2.7 bash -c "bundle check --path=vendor/bundle || bundle install --path=vendor/bundle"
          ;;
-       2)
+       1)
          rvm-exec 2.3.4 bash -c "bundle check --path=vendor/bundle || bundle install --path=vendor/bundle"
          ;;
-       3)
+       2)
          rvm-exec 2.4.1 bash -c "bundle check --path=vendor/bundle || bundle install --path=vendor/bundle"
          ;;
       esac
 
 test:
   override:
-    - case $CIRCLE_NODE_INDEX in 0) rvm-exec 2.1.10 bundle exec rake && bundle exec codeclimate-test-reporter ;; 1) rvm-exec 2.2.7 bundle exec rake && bundle exec codeclimate-test-reporter ;; 2) rvm-exec 2.3.4 bundle exec rake && bundle exec codeclimate-test-reporter ;; 3) rvm-exec 2.4.1 bundle exec rake && bundle exec codeclimate-test-reporter ;; esac:
+    - case $CIRCLE_NODE_INDEX in 0) rvm-exec 2.2.7 bundle exec rake ;; 1) rvm-exec 2.3.4 bundle exec rake ;; 2) rvm-exec 2.4.1 bundle exec rake && bundle exec codeclimate-test-reporter ;; esac:
         parallel: true