Add Ruby 3.1.0

Author: michaelbaudino

.travis.yml

@@ -20,8 +20,10 @@ env:
   global:
     - DOCKER_BUILDKIT=1
   jobs:
-    - RUBY_IMAGE_TAG=3.0.3        ALIAS_TAGS=3.0,latest
-    - RUBY_IMAGE_TAG=3.0.3-alpine ALIAS_TAGS=3.0-alpine,alpine
+    - RUBY_IMAGE_TAG=3.1.0        ALIAS_TAGS=3.1,latest
+    - RUBY_IMAGE_TAG=3.1.0-alpine ALIAS_TAGS=3.1-alpine,alpine
+    - RUBY_IMAGE_TAG=3.0.3        ALIAS_TAGS=3.0
+    - RUBY_IMAGE_TAG=3.0.3-alpine ALIAS_TAGS=3.0-alpine
     - RUBY_IMAGE_TAG=3.0.2
     - RUBY_IMAGE_TAG=3.0.2-alpine
     - RUBY_IMAGE_TAG=3.0.1