Replace datatime.timedelta() with datetime.timedelta() in codebase (

databricks#207)

## Fixes
Fixes databricks#206.

## Changes
With this PR, I am replacing `datatime.timedelta()` with
`datetime.timedelta()` in codebase

## Tests
<!-- 
How is this tested? Please see the checklist below and also describe any
other relevant tests
-->

- [x] `make test` run locally
- [x] `make fmt` applied
- [x] relevant integration tests applied

README.md

@@ -252,7 +252,7 @@ To find code examples that demonstrate how to call the Databricks SDK for Python
 When you invoke a long-running operation, the SDK provides a high-level API to _trigger_ these operations and _wait_ for the related entities
 to reach the correct state or return the error message in case of failure. All long-running operations return generic `Wait` instance with `result()`
 method to get a result of long-running operation, once it's finished. Databricks SDK for Python picks the most reasonable default timeouts for
-every method, but sometimes you may find yourself in a situation, where you'd want to provide `datatime.timedelta()` as the value of `timeout`
+every method, but sometimes you may find yourself in a situation, where you'd want to provide `datetime.timedelta()` as the value of `timeout`
 argument to `result()` method.
 
 There are a number of long-running operations in Databricks APIs such as managing:

docs/wait.md

@@ -3,7 +3,7 @@
 When you invoke a long-running operation, the SDK provides a high-level API to _trigger_ these operations and _wait_ for the related entities
 to reach the correct state or return the error message in case of failure. All long-running operations return generic `Wait` instance with `result()`
 method to get a result of long-running operation, once it's finished. Databricks SDK for Python picks the most reasonable default timeouts for
-every method, but sometimes you may find yourself in a situation, where you'd want to provide `datatime.timedelta()` as the value of `timeout`
+every method, but sometimes you may find yourself in a situation, where you'd want to provide `datetime.timedelta()` as the value of `timeout`
 argument to `result()` method.
 
 There are a number of long-running operations in Databricks APIs such as managing: