switch to a ruby version file for a consistent versioning that still allows commit-based ruby version updates

Author: mfleisch

.github/workflows/auto-dependency-update.yaml

@@ -15,7 +15,6 @@ jobs:
       - name: Setup Ruby
         uses: ruby/setup-ruby@v1
         with:
-          ruby-version: '3.3'
           working-directory: ./docs
           bundler-cache: false
 

.github/workflows/pr-build-check.yaml

@@ -20,7 +20,6 @@ jobs:
       - name: Setup Ruby and Install Gems
         uses: ruby/setup-ruby@v1
         with:
-          ruby-version: '3.3'
           working-directory: ./docs
           bundler-cache: true
 

.github/workflows/update_search_index.yaml

@@ -18,7 +18,6 @@ jobs:
       - name: Setup Ruby, Bundler, and Install Gems
         uses: ruby/setup-ruby@v1
         with:
-          ruby-version: '3.3'
           # This tells the action where to find the Gemfile
           working-directory: ./docs
           bundler-cache: true

docs/.ruby-version

@@ -0,0 +1 @@
+3.4