docs: Add mqtt submodule to RTD build configuration to correct file and delete similar file with typo in filename

.readthedocs.yml

@@ -1,22 +0,0 @@
-# .readthedocs.yml
-# Read the Docs configuration file
-# See https://docs.readthedocs.io/en/stable/config-file/v2.html for details
-
-# Required
-version: 2
-
-# Optionally build your docs in additional formats such as PDF and ePub
-formats:
-  - htmlzip
-  - pdf
-
-# Optionally set the version of Python and requirements required to build your docs
-python:
-  version: 2.7
-  install:
-    - requirements: docs/requirements.txt
-
-# We need to list all the submodules included in documenation build by Doxygen
-submodules: 
-  include:
-    - components/mqtt/esp-mqtt

.readthedocs.yml

@@ -15,3 +15,8 @@ python:
   version: 2.7
   install:
     - requirements: docs/requirements.txt
+
+# We need to list all the submodules included in documenation build by Doxygen
+submodules: 
+  include:
+    - components/mqtt/esp-mqtt