Pack files into tarball with random name

This is the only way to prevent Yarn from caching the contents. Yarn cache clean doesn't even eliminate the cache. Possibly a bug with Yarn?

Author: WesCossick

demo/.gitignore

@@ -7,7 +7,7 @@
 
 # testing
 /coverage
-package.tgz
+package-*.tgz
 
 # production
 /build

demo/package.json

@@ -20,7 +20,7 @@
 	"scripts": {
 		"start": "react-scripts start",
 		"build": "react-scripts build",
-		"pretest": "yarn remove react-accessible-dropdown-menu-hook && yarn --cwd ../ pack --filename package.tgz && yarn add file:./package.tgz",
+		"pretest": "RANDOM_STRING=$(LC_ALL=C tr -dc 'A-Za-z0-9' </dev/urandom | head -c 32 ; echo) && yarn remove react-accessible-dropdown-menu-hook && yarn --cwd ../ pack --filename package-$RANDOM_STRING.tgz && yarn add file:./package-$RANDOM_STRING.tgz && rm package-$RANDOM_STRING.tgz",
 		"test": "react-scripts test",
 		"posttest": "yarn remove react-accessible-dropdown-menu-hook && yarn add link:../",
 		"lint": "eslint --ext .ts,.js,.tsx . && prettier --check '**/*.{ts,js,tsx,css,html,json}'",