[#2] Update Upptime monitoring config

The monitoring configuration has been updated to consolidate the Onetime Secret homepage and staging site under a common "Homepage" name and ensure consistent health checks. The staging site check was revised to match the homepage using max response time and expected status codes instead of TCP ping for parity.

.upptimerc.yml

@@ -8,19 +8,22 @@ owner: onetimesecret
 repo: status
 
 sites:
-  - name: Onetime Secret
+  - name: Homepage
     url: https://onetimesecret.com/
     maxResponseTime: 5000
     expectedStatusCodes:
       - 200
       - 201
     headers:
       - "OTS-VIA: upptime"
-  - name: Staging
+  - name: Homepage (staging)
     url: $STAGING_HOST
-    port: 443
-    check: "tcp-ping"
-    ipv6: true
+    maxResponseTime: 5000
+    expectedStatusCodes:
+      - 200
+      - 201
+    headers:
+      - "OTS-VIA: upptime"
   - name: App Support
     url: https://app.onetimesecret.com/
   - name: API (v1)