## Changes
1. Change the **default-python** bundle template to set
`data_security_mode` of a cluster to SINGLE_USER
2. Change the **experimental-jobs-as-code** bundle template to set
`data_security_mode` of a cluster to SINGLE_USER
## Why
Explicitly adding this field saves experienced users from confusion onto
what security mode is applied to the cluster
## Tests
Changed existing unit and integration tests to pass with this change
$VARNAME is what we use for environment variables, it's good to
separate.
Some people use envsubst for homemade variable interpolation, it's also
good to have separation there.
## Changes
- Replace development version with $DEV_VERSION
- Update experimental-jobs-as-code to make use of it.
## Tests
- Existing tests.
- Using this in https://github.com/databricks/cli/pull/2213
## Changes
Add experimental-jobs-as-code template allowing defining jobs using
Python instead of YAML through the `databricks-bundles` PyPI package.
## Tests
Manually and acceptance tests.
Anton Nekipelov
Denis Bilenko
Gleb Kanterov