Fix checking for ":" in project dir on Windows for Docker containers

gns3server/compute/docker/docker_vm.py

@@ -323,8 +323,8 @@ class DockerVM(BaseNode):
         Creates the Docker container.
         """
 
-        if ":" in self.working_dir:
-            raise DockerError("Cannot create a Docker container with a project name containing a colon character (':')")
+        if ":" in os.path.splitdrive(self.working_dir)[1]:
+            raise DockerError("Cannot create a Docker container with a project directory containing a colon character (':')")
 
         try:
             image_infos = await self._get_image_information()