Update serverless client version to "2" in default-python template (#3083)

## Changes
This updates the client version in the default-python template to "2",
since that is the minimum required version for Databricks Free Edition.

## Tests
- [x] Manually tested on Databricks Free Edition.
- [x] Updated acceptance tests.

Author: lennartkats-db

NEXT_CHANGELOG.md

@@ -9,6 +9,7 @@
 ### CLI
 
 ### Bundles
+* Update client version to "2" for the serverless variation of the default-python template ([#3083](https://github.com/databricks/cli/pull/3083))
 * Fix reading dashboard contents when the sync root is different than the bundle root ([#3006](https://github.com/databricks/cli/pull/3006))
 * When glob for wheels is used, like "\*.whl", it will filter out different version of the same package and will only take the most recent version. ([#2982](https://github.com/databricks/cli/pull/2982))
 * When building Python artifacts as part of "bundle deploy" we no longer delete `dist`, `build`, `*egg-info` and `__pycache__` directories. ([#2982](https://github.com/databricks/cli/pull/2982))

acceptance/bundle/templates/default-python/classic/out.compare-vs-serverless.diff

@@ -27,7 +27,7 @@
 -          # Full documentation of this spec can be found at:
 -          # https://docs.databricks.com/api/workspace/jobs/create#environments-spec
 -          spec:
--            client: "1"
+-            client: "2"
 -            dependencies:
 -              - ../dist/*.whl
 +      job_clusters:

acceptance/bundle/templates/default-python/serverless/output/my_default_python/resources/my_default_python.job.yml

@@ -40,6 +40,6 @@ resources:
           # Full documentation of this spec can be found at:
           # https://docs.databricks.com/api/workspace/jobs/create#environments-spec
           spec:
-            client: "1"
+            client: "2"
             dependencies:
               - ../dist/*.whl

libs/template/templates/default-python/template/{{.project_name}}/resources/{{.project_name}}.job.yml.tmpl

@@ -74,7 +74,7 @@ resources:
           # Full documentation of this spec can be found at:
           # https://docs.databricks.com/api/workspace/jobs/create#environments-spec
           spec:
-            client: "1"
+            client: "2"
             dependencies:
               - ../dist/*.whl
 {{end}}{{ else }}