Add v2.1.1 release notes

Docs/manual/overview/installation.md

@@ -15,7 +15,7 @@ There are a number of ways to install Riptide, depending on what you're working
 1. In your Unity project, open the Package Manager (Window > Package Manager).
 2. Click the `+` (plus) button in the top left corner of the window.
 3. Select the *Add package from git URL...* option.
-4. Enter the following URL: `https://github.com/RiptideNetworking/Riptide.git?path=/Packages/Core#2.1.0`. To install a version other than v2.1.0, replace the `2.1.0` after the `#` with your chosen version number.
+4. Enter the following URL: `https://github.com/RiptideNetworking/Riptide.git?path=/Packages/Core#2.1.1`. To install a version other than v2.1.1, replace the `2.1.1` after the `#` with your chosen version number.
 5. Click 'Add' and wait for Riptide to be installed.
 
 If you have errors in your project after installation or intellisense isn't working for Riptide's classes, go to Edit > Preferences > External Tools, make sure the box next to *Git packages* is checked, and then click *Regenerate project files*.

Docs/manual/toc.yml

@@ -16,6 +16,8 @@
         href: updates/release-notes/v2.0.0.md
       - name: v2.1.0
         href: updates/release-notes/v2.1.0.md
+      - name: v2.1.1
+        href: updates/release-notes/v2.1.1.md
     - name: Upgrade Guides
       items:
       - name: Updating to v2

Docs/manual/updates/release-notes/v2.1.1.md

@@ -0,0 +1,18 @@
+---
+_description: Release notes for Riptide v2.1.1.
+---
+
+# v2.1.1 Release Notes
+
+Install this version with Unity's Package Manager using the following URL ([step-by-step instructions](~/manual/overview/installation.md#option-1-unity-package-manager)):
+```plaintext
+https://github.com/RiptideNetworking/Riptide.git?path=/Packages/Core#2.1.1
+```
+
+It can also be installed a number of [other ways](~/manual/overview/installation.md#net-projects) for use outside of Unity, including as a [NuGet package](https://www.nuget.org/packages/RiptideNetworking.Riptide).
+
+For a full list of source code changes, check out the [version comparison](https://github.com/RiptideNetworking/Riptide/compare/v2.1.0...v2.1.1) on GitHub.
+
+## Fixes
+
+- Fixed <code><xref:Riptide.Utils.Converter.SetBits(System.UInt64,System.Int32,System.UInt64[],System.Int32)></code> not overwriting bits properly in some cases, which could cause all sorts of problems, including incorrect disconnections due to "poor connection" quality ([#123](https://github.com/RiptideNetworking/Riptide/issues/123)).