{image-gallery} Patch version for updated doc (#8600)

* update version
* add help message for azdev style

Author: cxznmhdcxz

src/image-gallery/HISTORY.rst

@@ -3,6 +3,10 @@
 Release History
 ===============
 
+1.0.0b1
++++++++++++++++
+* Update module documentation.
+
 0.1.3
 +++++++++++++++
 * Update SDK

src/image-gallery/azext_image_gallery/_help.py

@@ -9,6 +9,15 @@
 from knack.help_files import helps  # pylint: disable=unused-import
 
 
+helps['sig create'] = """
+type: command
+short-summary: Create a Shared Image Gallery.
+examples:
+  - name: Create a Shared Image Gallery.
+    text: |
+        az sig create --resource-group MyResourceGroup --gallery-name MyGallery
+"""
+
 helps['sig show-community'] = """
 type: command
 short-summary: Get a gallery that has been community (preview).

src/image-gallery/azext_image_gallery/azext_metadata.json

@@ -1,4 +1,4 @@
 {
-    "azext.isExperimental": true,
+    "azext.isPreview": true,
     "azext.minCliCoreVersion": "2.3.0"
 }

src/image-gallery/setup.py

@@ -16,7 +16,7 @@
 
 # TODO: Confirm this is the right version number you want and it matches your
 # HISTORY.rst entry.
-VERSION = '0.1.3'
+VERSION = '1.0.0b1'
 
 # The full list of classifiers is available at
 # https://pypi.python.org/pypi?%3Aaction=list_classifiers