Merge pull request #358 from ESMValGroup/update_introduction_v2.12

Update 00-introduction.md

Author: LisaBock

.github/workflows/build-check-tutorial-site.yml

@@ -6,7 +6,7 @@ on:
 
 jobs:
   build:
-    runs-on: ubuntu-20.04
+    runs-on: "ubuntu-latest"
     steps:
     - uses: actions/checkout@v2
     - name: Setup Ruby

_episodes/00-introduction.md

@@ -2,7 +2,7 @@
 title: "Introduction"
 teaching: 5
 exercises: 10
-compatibility: ESMValTool v2.11.0
+compatibility: ESMValTool v2.12.0
 
 questions:
 - What is ESMValTool?