README Updates (#1)

* Docs link added to README, instructions for when swiftpm fails
* package resolve GitHub Action
* GitHub Action badge added to README

.github/workflows/swiftpm-resolve.yml

@@ -0,0 +1,19 @@
+name: resolve
+
+on:
+  push:
+    branches:
+      - "main"
+    tags:
+      - "!*"
+  pull_request:
+    branches:
+    - "*"
+
+jobs:
+  resolve:
+    runs-on: macOS-latest
+    steps:
+    - uses: actions/checkout@v1
+    - name: Build Package
+      run: swift package resolve

README.md

@@ -1,7 +1,13 @@
 # Agora Swift Package Manager
 
+<p align="center">
+  <img src="https://github.com/AgoraIO/AgoraRtcEngine_iOS/actions/workflows/swiftpm-resolve.yml/badge.svg"/>
+</p>
+
 Install Agora Video SDK easily with Swift Package Manager.
 
+[Click here for full documentation](https://docs.agora.io/en/Video/landing-page?platform=iOS).
+
 ## Installation
 
 Add the URL of this repository to your Xcode 11+ Project.
@@ -10,3 +16,8 @@ Go to File > Swift Packages > Add Package Dependency, and paste in the link to t
 
 `https://github.com/AgoraIO/AgoraRtcEngine_iOS`
 
+---
+
+If you have issues installing this Swift Package:
+
+In Xcode's File menu, select 'Swift Packages' and then 'Reset Package Caches'.