chore: fix docker build

Author: lakhansamani

.github/workflows/release.yaml

@@ -5,7 +5,7 @@ on:
 jobs:
   releases:
     name: Release Authorizer Binary
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-18.04
     steps:
       - uses: actions/checkout@v2
       - name: Install dependencies

README.md

@@ -95,13 +95,12 @@ binaries are baked with required deployment files and bundled. You can download
 
 - Mac OSX
 - Linux
-- Windows
 
 ### Step 1: Download and unzip bundle
 
 - Download the Bundle for the specific OS from the [release page](https://github.com/authorizerdev/authorizer/releases)
 
-> Note: For windows, it includes `.zip` file. For Linux & MacOS, it includes `.tar.gz` file.
+> Note: For windows, we recommend running using docker image to run authorizer.
 
 - Unzip using following command
 
@@ -111,12 +110,6 @@ binaries are baked with required deployment files and bundled. You can download
   tar -zxf AUTHORIZER_VERSION -c authorizer
   ```
 
-  - Windows
-
-  ```sh
-  unzip AUTHORIZER_VERSION
-  ```
-
 - Change directory to `authorizer`
 
   ```sh
@@ -137,12 +130,6 @@ Required environment variables are pre-configured in `.env` file. But based on t
   ./build/server
   ```
 
-  - For windows
-
-  ```sh
-  ./build/server.exe
-  ```
-
 > Note: For mac users, you might have to give binary the permission to execute. Here is the command you can use to grant permission `xattr -d com.apple.quarantine build/server`
 
 ## Install instance on Heroku