Update required CMake

CMakeLists.txt

@@ -1,4 +1,4 @@
-cmake_minimum_required(VERSION 3.1)
+cmake_minimum_required(VERSION 3.13)
 project(aws-c-mqtt C)
 
 option(ASSERT_LOCK_HELD "Enable ASSERT_SYNCED_DATA_LOCK_HELD for checking thread issue" OFF)
@@ -68,7 +68,6 @@ file(GLOB MQTT_SRC
         ${AWS_MQTT_SRC}
         )
 
-aws_set_common_policies()
 add_library(${PROJECT_NAME} ${MQTT_HEADERS} ${MQTT_SRC})
 aws_set_common_properties(${PROJECT_NAME})
 aws_prepare_symbol_visibility_args(${PROJECT_NAME} "AWS_MQTT")

README.md

@@ -4,13 +4,13 @@ C99 implementation of the MQTT 3.1.1 and MQTT 5 specifications.
 
 ## License
 
-This library is licensed under the Apache 2.0 License. 
+This library is licensed under the Apache 2.0 License.
 
 ## Usage
 
 ### Building
 
-CMake 3.1+ is required to build.
+CMake 3.13+ is required to build.
 
 `<install-path>` must be an absolute path in the following instructions.
 
@@ -203,6 +203,6 @@ the wire. For QoS 1, as soon as PUBACK comes back. For QoS 2, PUBCOMP. `topic` a
 ```c
 int aws_mqtt_client_connection_ping(struct aws_mqtt_client_connection *connection);
 ```
-Sends a PINGREQ packet to the server. 
+Sends a PINGREQ packet to the server.
 
 [aws-c-io]: https://github.com/awslabs/aws-c-io