Update yarn dependencies

Bump terser and requirejs.

Makefile

@@ -25,7 +25,7 @@ Bastelstu.be.Chat.babel.js: Bastelstu.be.Chat.js .babelrc
 	yarn run babel $< --out-file $@
 
 Bastelstu.be.Chat.js: $(JS_MODULE_FILES)
-	yarn run r.js -o require.build.js
+	yarn run r_js -o require.build.js
 
 clean:
 	-rm -f files.tar

package.json

@@ -3,7 +3,7 @@
     "@babel/cli": "^7.0.0",
     "@babel/core": "^7.0.0",
     "@babel/preset-env": "^7.0.0",
-    "requirejs": "^2.3.5",
-    "terser": "^3.8.1"
+    "requirejs": "^2.3.6",
+    "terser": "^4.6.7"
   }
 }