feat: Tasks v1 readiness (#3222)

Pr that collects all the changes to tasks from previous prs:
-
#3202
-
#3170
-
#3113

**Note**: look at the last commit, added very small changes to
documentation and code (around 8 lines)

MIGRATION_GUIDE.md

@@ -6,9 +6,150 @@ across different versions.
 
 > [!TIP]
 > We highly recommend upgrading the versions one by one instead of bulk upgrades.
-
+ 
 ## v0.98.0 ➞ v0.99.0
 
+### snowflake_tasks data source changes
+
+New filtering options:
+- `with_parameters`
+- `like`
+- `in`
+- `starts_with`
+- `root_only`
+- `limit`
+
+New output fields
+- `show_output`
+- `parameters`
+
+Breaking changes:
+- `database` and `schema` are right now under `in` field
+
+Before:
+```terraform
+data "snowflake_tasks" "old_tasks" {
+  database = "<database_name>"
+  schema = "<schema_name>"
+}
+```
+After:
+```terraform
+data "snowflake_tasks" "new_tasks" {
+  in {
+    # for IN SCHEMA specify:
+    schema = "<database_name>.<schema_name>"
+    
+    # for IN DATABASE specify:
+    database = "<database_name>"
+  }
+}
+```
+- `tasks` field now organizes output of show under `show_output` field and the output of show parameters under `parameters` field.
+
+Before:
+```terraform
+output "simple_output" {
+  value = data.snowflake_tasks.test.tasks[0].name
+}
+```
+After:
+```terraform
+output "simple_output" {
+  value = data.snowflake_tasks.test.tasks[0].show_output[0].name
+}
+```
+
+### snowflake_task resource changes
+New fields:
+- `config` - enables to specify JSON-formatted metadata that can be retrieved in the `sql_statement` by using [SYSTEM$GET_TASK_GRAPH_CONFIG](https://docs.snowflake.com/en/sql-reference/functions/system_get_task_graph_config).
+- `show_output` and `parameters` fields added for holding SHOW and SHOW PARAMETERS output (see [raw Snowflake output](./v1-preparations/CHANGES_BEFORE_V1.md#raw-snowflake-output)).
+- Added support for finalizer tasks with `finalize` field. It conflicts with `after` and `schedule` (see [finalizer tasks](https://docs.snowflake.com/en/user-guide/tasks-graphs#release-and-cleanup-of-task-graphs)).
+
+Changes:
+- `enabled` field changed to `started` and type changed to string with only boolean values available (see ["empty" values](./v1-preparations/CHANGES_BEFORE_V1.md#empty-values)). It is also now required field, so make sure it's explicitly set (previously it was optional with the default value set to `false`).
+- `allow_overlapping_execution` type was changed to string with only boolean values available (see ["empty" values](./v1-preparations/CHANGES_BEFORE_V1.md#empty-values)). Previously, it had the default set to `false` which will be migrated. If nothing will be set the provider will plan the change to `default` value. If you want to make sure it's turned off, set it explicitly to `false`.
+
+Before:
+```terraform
+resource "snowflake_task" "example" {
+  # ...
+  enabled = true
+  # ...
+}
+```
+After:
+```terraform
+resource "snowflake_task" "example" {
+  # ...
+  started = true
+  # ...
+}
+```
+- `schedule` field changed from single value to a nested object that allows for specifying either minutes or cron
+
+Before:
+```terraform
+resource "snowflake_task" "example" {
+  # ...
+  schedule = "5 MINUTES"
+  # or
+  schedule = "USING CRON * * * * * UTC"
+  # ...
+}
+```
+After:
+```terraform
+resource "snowflake_task" "example" {
+  # ...
+  schedule {
+    minutes = 5
+    # or
+    using_cron = "* * * * * UTC"
+  }
+  # ...
+}
+```
+- All task parameters defined in [the Snowflake documentation](https://docs.snowflake.com/en/sql-reference/parameters) added into the top-level schema and removed `session_parameters` map.
+
+Before:
+```terraform
+resource "snowflake_task" "example" {
+  # ...
+  session_parameters = {
+    QUERY_TAG = "<query_tag>"
+  }
+  # ...
+}
+```
+After:
+```terraform
+resource "snowflake_task" "example" {
+  # ...
+  query_tag = "<query_tag>"
+  # ...
+}
+```
+
+- `after` field type was changed from `list` to `set` and the values were changed from names to fully qualified names.
+
+Before:
+```terraform
+resource "snowflake_task" "example" {
+  # ...
+  after = ["<task_name>", snowflake_task.some_task.name]
+  # ...
+}
+```
+After:
+```terraform
+resource "snowflake_task" "example" {
+  # ...
+  after = ["<database_name>.<schema_name>.<task_name>", snowflake_task.some_task.fully_qualified_name]
+  # ...
+}
+```
+
 ### *(new feature)* snowflake_tags datasource
 Added a new datasource enabling querying and filtering tags. Notes:
 - all results are stored in `tags` field.