Merge tag 'v1.5.13' into matthew/p2p

[Full Changelog](https://github.com/vector-im/riot-web/compare/v1.5.13-rc.1...v1.5.13)
* Upgrade to JS SDK 5.1.1 and React SDK 2.2.3

webpack.config.js

@@ -40,6 +40,7 @@ module.exports = (env, argv) => {
             "sql_wasm": "./node_modules/sql.js/dist/sql-wasm.wasm",
             "dendrite_wasm": "./src/vector/dendrite.wasm",
             "wasm_exec": "./src/vector/wasm_exec.js",
+            "usercontent": "./node_modules/matrix-react-sdk/src/usercontent/index.js",
 
             // CSS themes
             "theme-light": "./node_modules/matrix-react-sdk/res/themes/light/css/light.scss",
@@ -314,7 +315,7 @@ module.exports = (env, argv) => {
                 // HtmlWebpackPlugin will screw up our formatting like the names
                 // of the themes and which chunks we actually care about.
                 inject: false,
-                excludeChunks: ['mobileguide'],
+                excludeChunks: ['mobileguide', 'usercontent'],
                 minify: argv.mode === 'production',
                 vars: {
                     og_image_url: og_image_url,
@@ -328,6 +329,14 @@ module.exports = (env, argv) => {
                 minify: argv.mode === 'production',
                 chunks: ['mobileguide'],
             }),
+
+            // This is the usercontent sandbox's entry point (separate for iframing)
+            new HtmlWebpackPlugin({
+                template: './node_modules/matrix-react-sdk/src/usercontent/index.html',
+                filename: 'usercontent/index.html',
+                minify: argv.mode === 'production',
+                chunks: ['usercontent'],
+            }),
         ],
 
         output: {