[Internal] Test that Jobs API endpoints are pinned to 2.1 (#319)

## Changes
<!-- Summary of your changes that are easy to understand -->
Adds regression tests to ensure required Jobs endpoints say pinned to
API 2.1

## Tests
<!-- How is this tested? -->
Unit tests.

Author: ricardoc-db

databricks-sdk-java/src/test/java/com/databricks/sdk/service/jobs/JobsImplTest.java

@@ -0,0 +1,89 @@
+package com.databricks.sdk.service.jobs;
+
+import static org.mockito.ArgumentMatchers.*;
+import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.when;
+
+import com.databricks.sdk.core.ApiClient;
+import org.junit.jupiter.api.Test;
+import org.mockito.Mockito;
+
+public class JobsImplTest {
+
+  /*
+   * API 2.1 pinned endpoints check
+   * See: https://databricks.atlassian.net/browse/JOBS-19304
+   */
+
+  @Test
+  public void testJobsCreateUsesApi2_1() {
+    ApiClient apiClient = Mockito.mock(ApiClient.class);
+    String expectedPath = "/api/2.1/jobs/create";
+    when(apiClient.POST(eq(expectedPath), any(), any(), any())).thenReturn(null);
+
+    JobsService jobs = new JobsImpl(apiClient);
+    jobs.create(new CreateJob());
+
+    verify(apiClient).POST(eq(expectedPath), any(), any(), any());
+  }
+
+  @Test
+  public void testJobsGetUsesApi2_1() {
+    ApiClient apiClient = Mockito.mock(ApiClient.class);
+    String expectedPath = "/api/2.1/jobs/get";
+    when(apiClient.GET(eq(expectedPath), any(), any(), any())).thenReturn(null);
+
+    JobsService jobs = new JobsImpl(apiClient);
+    jobs.get(new GetJobRequest());
+
+    verify(apiClient).GET(eq(expectedPath), any(), any(), any());
+  }
+
+  @Test
+  public void testJobsListUsesApi2_1() {
+    ApiClient apiClient = Mockito.mock(ApiClient.class);
+    String expectedPath = "/api/2.1/jobs/list";
+    when(apiClient.GET(eq(expectedPath), any(), any(), any())).thenReturn(null);
+
+    JobsService jobs = new JobsImpl(apiClient);
+    jobs.list(new ListJobsRequest());
+
+    verify(apiClient).GET(eq(expectedPath), any(), any(), any());
+  }
+
+  @Test
+  public void testJobsUpdateUsesApi2_1() {
+    ApiClient apiClient = Mockito.mock(ApiClient.class);
+    String expectedPath = "/api/2.1/jobs/update";
+    when(apiClient.POST(eq(expectedPath), any(), any(), any())).thenReturn(null);
+
+    JobsService jobs = new JobsImpl(apiClient);
+    jobs.update(new UpdateJob());
+
+    verify(apiClient).POST(eq(expectedPath), any(), any(), any());
+  }
+
+  @Test
+  public void testJobsResetUsesApi2_1() {
+    ApiClient apiClient = Mockito.mock(ApiClient.class);
+    String expectedPath = "/api/2.1/jobs/reset";
+    when(apiClient.POST(eq(expectedPath), any(), any(), any())).thenReturn(null);
+
+    JobsService jobs = new JobsImpl(apiClient);
+    jobs.reset(new ResetJob());
+
+    verify(apiClient).POST(eq(expectedPath), any(), any(), any());
+  }
+
+  @Test
+  public void testJobsListRunsUsesApi2_1() {
+    ApiClient apiClient = Mockito.mock(ApiClient.class);
+    String expectedPath = "/api/2.1/jobs/runs/list";
+    when(apiClient.GET(eq(expectedPath), any(), any(), any())).thenReturn(null);
+
+    JobsService jobs = new JobsImpl(apiClient);
+    jobs.listRuns(new ListRunsRequest());
+
+    verify(apiClient).GET(eq(expectedPath), any(), any(), any());
+  }
+}