feat: add support for macos

Signed-off-by: Amogh Lele <amolele@gmail.com>

example/macos/Runner/Release.entitlements

@@ -0,0 +1,10 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
+<plist version="1.0">
+<dict>
+	<key>com.apple.security.app-sandbox</key>
+	<true/>
+    <key>com.apple.security.network.client</key>
+    <true/>
+</dict>
+</plist>