Update Pagerduty setup instructions

Signed-off-by: GitHub <noreply@github.com>

plugins/pagerduty/README.md

@@ -28,12 +28,12 @@ Add it to the app in `plugins.ts`:
 export { plugin as Pagerduty } from '@backstage/plugin-pagerduty';
 ```
 
-Add it to the `EntityPage.ts`:
+Add it to the `EntityPage.tsx`:
 
 ```ts
 import {
   isPluginApplicableToEntity as isPagerDutyAvailable,
-  PagerDutyCard,
+  EntityPagerDutyCard,
 } from '@backstage/plugin-pagerduty';
 // add to code
 {
@@ -45,6 +45,18 @@ import {
 }
 ```
 
+Add the proxy configuration in `app-config.yaml`
+
+```yaml
+proxy:
+  ...
+  '/pagerduty':
+    target: https://api.pagerduty.com
+    headers:
+      Authorization:
+        $env: PAGERDUTY_TOKEN
+```
+
 ## Client configuration
 
 If you want to override the default URL for events, you can add it to `app-config.yaml`.