20190701 add (Azure#14319)

Author: RAY-316

specification/iothub/resource-manager/readme.python.md

@@ -35,6 +35,7 @@ batch:
   - tag: package-preview-2021-03
   - tag: package-2020-03
   - tag: package-2019-11
+  - tag: package-preview-2019-07
   - tag: package-2019-03
   - tag: package-2018-04
   - tag: package-2018-01
@@ -48,6 +49,7 @@ batch:
   - tag: package-preview-2021-03
   - tag: package-2020-03
   - tag: package-2019-11
+  - tag: package-preview-2019-07
   - tag: package-2019-03
   - tag: package-2018-04
   - tag: package-2018-01
@@ -102,6 +104,19 @@ python:
   output-folder: $(python-sdks-folder)/iothub/azure-mgmt-iothub/azure/mgmt/iothub/v2019_11_04
 ```
 
+### Tag: package-preview-2019-07 and python
+
+These settings apply only when `--tag=package-preview-2019-07 --python` is specified on the command line.
+Please also specify `--python-sdks-folder=<path to the root directory of your azure-sdk-for-python clone>`.
+
+``` yaml $(tag) == 'package-preview-2019-07' && $(python)
+namespace: azure.mgmt.iothub.v2019_07_01_preview
+output-folder: $(python-sdks-folder)/iothub/azure-mgmt-iothub/azure/mgmt/iothub/v2019_07_01_preview
+python:
+  namespace: azure.mgmt.iothub.v2019_07_01_preview
+  output-folder: $(python-sdks-folder)/iothub/azure-mgmt-iothub/azure/mgmt/iothub/v2019_07_01_preview
+```
+
 ### Tag: package-2019-03 and python
 
 These settings apply only when `--tag=package-2019-03 --python` is specified on the command line.