Revert Ruby bump until CF Buildpacks support it

.ruby-version

@@ -1 +1 @@
-3.1.0
+3.0.3

Dockerfile

@@ -1,5 +1,5 @@
 # Build compilation image
-FROM ruby:3.1.0-alpine3.14 as builder
+FROM ruby:3.0.3-alpine3.14 as builder
 
 # The application runs from /app
 WORKDIR /app
@@ -45,7 +45,7 @@ RUN rm -rf node_modules log tmp && \
       find /usr/local/bundle/gems -name "*.html" -delete
 
 # Build runtime image
-FROM ruby:3.1.0-alpine as production
+FROM ruby:3.0.3-alpine as production
 
 # The application runs from /app
 WORKDIR /app

Gemfile

@@ -3,7 +3,7 @@
 source "https://rubygems.org"
 git_source(:github) { |repo| "https://github.com/#{repo}.git" }
 
-ruby "3.1.0"
+ruby "3.0.3"
 
 # Bundle edge Rails instead: gem 'rails', github: 'rails/rails', branch: 'main'
 gem "rails", "~> 7.0.1"

Gemfile.lock

@@ -464,7 +464,7 @@ DEPENDENCIES
   webpacker (~> 5.0)
 
 RUBY VERSION
-   ruby 3.1.0p0
+   ruby 3.0.3p157
 
 BUNDLED WITH
    2.3.3