Uses gradle v 6.8, causes issues on first compile

The error message tells you how to fix it (adding a file called gradle-wrapper.properties) but it would be nice if this project could compile out of the box. I couldn't go through the tutorial because there were numerous discrepancies.

Start by reproducing the first compile failure and inspect the Gradle wrapper setup, especially the gradle-wrapper.properties file mentioned in the error. Done means the codelab compiles out of the box and the reported tutorial discrepancies have been addressed.

Written by the indexing model from the issue text.