docs(readme): add UTM tracking to e2b.dev links (#230)

Author: drankou

README.md

@@ -12,7 +12,7 @@ Powered by the [E2B SDK](https://github.com/e2b-dev/code-interpreter).
 ## Features
 
 - Based on Next.js 14 (App Router, Server Actions), shadcn/ui, TailwindCSS, Vercel AI SDK.
-- Uses the [E2B SDK](https://github.com/e2b-dev/code-interpreter) by [E2B](https://e2b.dev) to securely execute code generated by AI.
+- Uses the [E2B SDK](https://github.com/e2b-dev/code-interpreter) by [E2B](https://e2b.dev/?utm_source=github&utm_medium=referral&utm_campaign=readme&utm_content=fragments) to securely execute code generated by AI.
 - Streaming in the UI.
 - Can install and use any package from npm, pip.
 - Supported stacks ([add your own](#adding-custom-personas)):
@@ -42,7 +42,7 @@ Powered by the [E2B SDK](https://github.com/e2b-dev/code-interpreter).
 
 - [git](https://git-scm.com)
 - Recent version of [Node.js](https://nodejs.org) and npm package manager
-- [E2B API Key](https://e2b.dev)
+- [E2B API Key](https://e2b.dev/?utm_source=github&utm_medium=referral&utm_campaign=readme&utm_content=fragments)
 - LLM Provider API Key
 
 ### 1. Clone the repository
@@ -72,7 +72,7 @@ npm i
 Create a `.env.local` file and set the following:
 
 ```sh
-# Get your API key here - https://e2b.dev/
+# Get your API key here - https://e2b.dev/?utm_source=github&utm_medium=referral&utm_campaign=readme&utm_content=fragments
 E2B_API_KEY="your-e2b-api-key"
 
 # OpenAI API Key
@@ -138,7 +138,7 @@ npm run build
 
 ### Adding custom personas
 
-1. Make sure [E2B CLI](https://e2b.dev/docs/cli) is installed and you're logged in.
+1. Make sure [E2B CLI](https://e2b.dev/docs/cli?utm_source=github&utm_medium=referral&utm_campaign=readme&utm_content=fragments) is installed and you're logged in.
 
 2. Add a new folder under [sandbox-templates/](sandbox-templates/)