chore: make cron secret required (#2843)

apps/docs/app/developer-docs/contributing/get-started/page.mdx

@@ -21,6 +21,7 @@ We are so happy that you are interested in contributing to Formbricks 🤗 There
 - **How to create a service**: [Read this document to understand how we use services](https://formbricks.notion.site/How-to-create-a-service-8e0c035704bb40cb9ea5e5beeeeabd67?pvs=4). This is particulalry important when you need to write a new one.
 
 ## Talk to us first
+
 We highly recommend connecting with us on [Discord server](https://formbricks.com/discord) before you ship a contribution. This will increase the likelihood of your PR being merged. And it will decrease the likelihood of you wasting your time :)
 
 ## Contributor License Agreement (CLA)
@@ -90,14 +91,29 @@ cp .env.example .env
    </CodeGroup>
 </Col>
 
-4. Generate & set some secret values mandatory for the `ENCRYPTION_KEY` & `NEXTAUTH_SECRET` in the .env file. You can use the following command to generate the random string of required length:
+4. Generate & set some secret values mandatory for the `ENCRYPTION_KEY`, `NEXTAUTH_SECRET` and `CRON_SECRET` in the .env file. You can use the following command to generate the random string of required length:
 
+- For Linux
 <Col>
-   <CodeGroup title="Set value of ENCRYPTION_KEY">
+   <CodeGroup title="For Linux">
 
 ```bash
 sed -i '/^ENCRYPTION_KEY=/c\ENCRYPTION_KEY='$(openssl rand -hex 32) .env
 sed -i '/^NEXTAUTH_SECRET=/c\NEXTAUTH_SECRET='$(openssl rand -hex 32) .env
+sed -i '/^CRON_SECRET=/c\CRON_SECRET='$(openssl rand -hex 32) .env
+```
+
+   </CodeGroup>
+</Col>
+
+- For Mac   
+<Col>
+   <CodeGroup title="For Mac">
+
+```bash
+sed -i '' '/^ENCRYPTION_KEY=/s|.*|ENCRYPTION_KEY='$(openssl rand -hex 32)'|' .env
+sed -i '' '/^NEXTAUTH_SECRET=/s|.*|NEXTAUTH_SECRET='$(openssl rand -hex 32)'|' .env
+sed -i '' '/^CRON_SECRET=/s|.*|CRON_SECRET='$(openssl rand -hex 32)'|' .env
 ```
 
    </CodeGroup>
@@ -149,4 +165,4 @@ pnpm build
 ```
 
 </CodeGroup>
-</Col>
+</Col>