Update CHANGELOG for v1.8.3 (#723)

* Update CHANGELOG for v1.8.3

* Fix typo

* Fixup format

Author: rjmholt

Diff for: CHANGELOG.md

@@ -1,5 +1,17 @@
 # PowerShell Editor Services Release History
 
+## v1.8.3
+### Wednesday, August 15, 2018
+
+#### Fixes and Improvements
+
+- [PowerShell/PowerShellEditorServices #722](https://github.com/PowerShell/PowerShellEditorServices/pull/722) -
+  Add VSTS signing step
+- [PowerShell/PowerShellEditorServices #717](https://github.com/PowerShell/PowerShellEditorServices/pull/717) -
+  Increment version for prerelease
+- [PowerShell/PowerShellEditorServices #715](https://github.com/PowerShell/PowerShellEditorServices/pull/715) -
+  Reduce allocations when parsing files (Thanks @mattpwhite!)
+
 ## v1.8.2
 ### Thursday, July 26, 2018
 
@@ -8,17 +20,17 @@
 - [PowerShell/PowerShellEditorServices #712](https://github.com/PowerShell/PowerShellEditorServices/pull/712) -
   workaround to support inmemory:// (#712)
 - [PowerShell/PowerShellEditorServices #706](https://github.com/PowerShell/PowerShellEditorServices/pull/706) -
-  Go To Definition works with different Ast types (#706)
+  Go To Definition works with different Ast types
 - [PowerShell/PowerShellEditorServices #707](https://github.com/PowerShell/PowerShellEditorServices/pull/707) -
-  fix stdio passing (#707)
+  fix stdio passing
 - [PowerShell/PowerShellEditorServices #709](https://github.com/PowerShell/PowerShellEditorServices/pull/709) -
-  Stop Diagnostic logging from logging to stdio when the communication protocol is set to stdio (#709)
+  Stop Diagnostic logging from logging to stdio when the communication protocol is set to stdio
 - [PowerShell/PowerShellEditorServices #710](https://github.com/PowerShell/PowerShellEditorServices/pull/710) -
-  stdio should only launch language service not debug (#710)
+  stdio should only launch language service not debug
 - [PowerShell/PowerShellEditorServices #705](https://github.com/PowerShell/PowerShellEditorServices/pull/705) -
-  Fix load order of PSSA modules (#705)
+  Fix load order of PSSA modules
 - [PowerShell/PowerShellEditorServices #704](https://github.com/PowerShell/PowerShellEditorServices/pull/704) -
-  Do not enable PSAvoidTrailingWhitespace rule by default as it currenly flags whitespace-only lines as well (#704) (Thanks @bergmeister!)
+  Do not enable PSAvoidTrailingWhitespace rule by default as it currenly flags whitespace-only lines as well (Thanks @bergmeister!)
 
 ## v1.8.1
 ### Wednesday, July 11, 2018