Update kotlin usage of okhttp due to bump 3.x->4.xwhich is binary compatible but not source compatible

Signed-off-by: Andy Scherzinger <info@andy-scherzinger.de>

app/src/main/java/com/nextcloud/talk/controllers/ChatController.kt

@@ -1267,7 +1267,7 @@ class ChatController(args: Bundle) :
         val xChatLastCommonRead = response.headers().get("X-Chat-Last-Common-Read")?.let {
             Integer.parseInt(it)
         }
-        if (response.headers().size() > 0 && !TextUtils.isEmpty(xChatLastGivenHeader)) {
+        if (response.headers().size > 0 && !TextUtils.isEmpty(xChatLastGivenHeader)) {
 
             val header = Integer.parseInt(xChatLastGivenHeader!!)
             if (header > 0) {

app/src/main/java/com/nextcloud/talk/jobs/ContactAddressBookWorker.kt

@@ -54,8 +54,8 @@ import io.reactivex.Observer
 import io.reactivex.android.schedulers.AndroidSchedulers
 import io.reactivex.disposables.Disposable
 import io.reactivex.schedulers.Schedulers
-import okhttp3.MediaType
-import okhttp3.RequestBody
+import okhttp3.MediaType.Companion.toMediaTypeOrNull
+import okhttp3.RequestBody.Companion.toRequestBody
 import javax.inject.Inject
 
 @AutoInjector(NextcloudTalkApplication::class)
@@ -122,7 +122,7 @@ class ContactAddressBookWorker(val context: Context, workerParameters: WorkerPar
             ncApi.searchContactsByPhoneNumber(
                 ApiUtils.getCredentials(currentUser.username, currentUser.token),
                 ApiUtils.getUrlForSearchByNumber(currentUser.baseUrl),
-                RequestBody.create(MediaType.parse("application/json"), json)
+                json.toRequestBody("application/json".toMediaTypeOrNull())
             )
                 .subscribeOn(Schedulers.io())
                 .observeOn(AndroidSchedulers.mainThread())

app/src/main/java/com/nextcloud/talk/jobs/UploadAndShareFilesWorker.kt

@@ -44,7 +44,7 @@ import io.reactivex.Observer
 import io.reactivex.android.schedulers.AndroidSchedulers
 import io.reactivex.disposables.Disposable
 import io.reactivex.schedulers.Schedulers
-import okhttp3.MediaType
+import okhttp3.MediaType.Companion.toMediaTypeOrNull
 import okhttp3.RequestBody
 import retrofit2.Response
 import java.io.File
@@ -103,7 +103,7 @@ class UploadAndShareFilesWorker(val context: Context, workerParameters: WorkerPa
             val input: InputStream = context.contentResolver.openInputStream(sourcefileUri)!!
             val buf = ByteArray(input.available())
             while (input.read(buf) != -1);
-            requestBody = RequestBody.create(MediaType.parse("application/octet-stream"), buf)
+            requestBody = RequestBody.create("application/octet-stream".toMediaTypeOrNull(), buf)
         } catch (e: Exception) {
             Log.e(javaClass.simpleName, "failed to create RequestBody for $sourcefileUri", e)
         }