Update supported ruby versions

Author: wpolicarpo

circle.yml

@@ -19,9 +19,9 @@ dependencies:
     - sudo ./test/bin/install-freetds.sh
     - tsql -C
     - rvm-exec 2.2.10 bundle install
-    - rvm-exec 2.3.7 bundle install
-    - rvm-exec 2.4.4 bundle install
-    - rvm-exec 2.5.1 bundle install
+    - rvm-exec 2.3.8 bundle install
+    - rvm-exec 2.4.5 bundle install
+    - rvm-exec 2.5.3 bundle install
 
 database:
   override:
@@ -33,6 +33,6 @@ database:
 test:
   override:
     - rvm-exec 2.2.10 bundle exec rake test
-    - rvm-exec 2.3.7 bundle exec rake test
-    - rvm-exec 2.4.4 bundle exec rake test
-    - rvm-exec 2.5.1 bundle exec rake test
+    - rvm-exec 2.3.8 bundle exec rake test
+    - rvm-exec 2.4.5 bundle exec rake test
+    - rvm-exec 2.5.3 bundle exec rake test