MC-6298: Beta 3 docs release notes

Removed extra spaces and added version ^1.0.0 to install composer command.

Author: bdenham

docs/getting-started/install-pagebuilder.md

@@ -18,7 +18,7 @@ If you have had a previous version of Magento 2.3.0 or Page Builder installed yo
 
 3. Navigate to the root of the project and require the `magento/module-page-builder-commerce` package:
     ```
-    composer require magento/page-builder-commerce
+    composer require magento/page-builder-commerce:^1.0.0
     ```
     
 4. Enable the module within Magento:

docs/release-notes.md

@@ -5,18 +5,12 @@ Here are the Page Builder beta release notes and the higher priority known issue
 ## Beta 3 - December 19, 2018
 
 - Improved: Handling of invalid Google Maps API keys <!-- MC-5723 -->
-
 - Removed: Legacy overlay transparency field from banner & slider in favor of using the color picker <!-- MC-3895 -->
-
 - Resolved: Box sizing issues on storefront and Admin <!-- MC-5079 --> 
-
 - Resolved: Issue with initiation of tabs breaking in certain scenarios <!-- MC-5363 --> 
-
 - Resolved: Performance issues with "Edit with Page Builder" button in category and product areas <!-- MC-5403 --> 
-
 - Resolved: Numerous issues within staging slide out <!-- MC-5423 --> 
 
-
 ## Beta 2 - December 10, 2018
 
 - Resolved: Image inside Text Content Type is scaled on stage <!-- MC-3509 -->