fix typo in InvalidBackupJob exception (spatie#635)

* fix typo in InvalidBackupJob exception

* update test to match InvalidBackupJob exception

Author: joepriest

src/Exceptions/InvalidBackupJob.php

@@ -13,7 +13,7 @@ public static function noDestinationsSpecified(): self
 
     public static function destinationDoesNotExist(string $diskName): self
     {
-        return new static("There is not backup destination with a disk named `{$diskName}`");
+        return new static("There is no backup destination with a disk named `{$diskName}`");
     }
 
     public static function noFilesToBeBackedUp(): self

tests/Integration/BackupCommandTest.php

@@ -217,7 +217,7 @@ public function it_will_fail_when_trying_to_backup_to_an_non_existing_diskname()
 
         $this->assertEquals(1, $resultCode);
 
-        $this->seeInConsoleOutput('There is not backup destination with a disk named');
+        $this->seeInConsoleOutput('There is no backup destination with a disk named');
 
         $this->assertFileNotExistsOnDisk($this->expectedZipPath, 'local');
         $this->assertFileNotExistsOnDisk($this->expectedZipPath, 'secondLocal');