Update: bump Ruby to 3.3 (#335)

Seems 3.0 is too old for latest Jekyll

Author: TrueBrain

.github/workflows/publish.yml

@@ -40,7 +40,7 @@ jobs:
     - name: Set up Ruby
       uses: ruby/setup-ruby@v1
       with:
-        ruby-version: 3.0
+        ruby-version: '3.3'
         bundler-cache: true
 
     - name: Set up Python

.github/workflows/testing.yml

@@ -31,7 +31,7 @@ jobs:
     - name: Set up Ruby
       uses: ruby/setup-ruby@v1
       with:
-        ruby-version: 3.0
+        ruby-version: '3.3'
         bundler-cache: true
 
     - name: Set up Python