Fix offset issue in tut

Chore: Grab stragglers

Merge pull request #1060 from hasura/robdominguez/doc-2429-learn-site-out-of-date-messaging-per-tutorial

Add isMaintained key-value to unmaintained courses

Chore: Update gitbook hash and local dev echos

Merge pull request #1059 from hasura/robdominguez/doc-2357-remove-references-to-absent-sample-apps-in-learn-courses

Chore: Remove sample app references

Merge pull request #1058 from hasura/rob/fix-nextjs-link

Remove reference to deployed project

learn-graphql: deployment version change

learn-graphql: deployment version change

learn-graphql: update gatsby gitbook theme

Merge pull request #1056 from hasura/rob/docs/update-introduction-for-apollo-react

Update introduction.md Fixes #1055

backend-stack: update content with python (#1049)