Tasks in "Environment Variables" chapter (page 116) do not work for ubuntu2004

Fails with:
```
TASK [Add an environment variable to the remote user's shell.] *****************
fatal: [ubuntu2004]: FAILED! => changed=false
msg: Destination /root/.bash_profile does not exist !
rc: 257
```
Seems to work OK with `geerlingguy/centos7` and `geerlingguy/centos8` images. But since it's not mentioned in that chapter that CentOS should be used and the previous exercise was for Solr in **Ubuntu**, my first assumption was to try with Ubuntu. Perhaps it's worth either making the play more universal or adding a note that this example works with CentOS