Build with Go 1.27.3

Go 1.27.2 and 1.27.3 are security releases; 1.27.3 makes crypto/x509
reject chains through the eight compromised eMudhra intermediate CAs.
ntfy's outbound TLS (Firebase, web push, Stripe, Twilio, S3, upstream)
only gets that by being rebuilt.

The bump was held at 1.27.1 because staticcheck v0.8.1 could not read
Go 1.27.2's export data; staticcheck 2026.2.2 (v0.8.2) can, and is
clean. text/template is unchanged, so only GENERATED_FROM moves.

.go-version

@@ -1 +1 @@
-1.27.1
+1.27.3

docs/releases.md

@@ -2219,6 +2219,7 @@ and the [ntfy Android app](https://github.com/binwiederhier/ntfy-android/release
 
 **Security:**
 
+* Build with Go 1.27.3, which includes the security fixes of Go 1.27.2 (`crypto/tls`, `net/http`, `html/template` and others) and 1.27.3 (`crypto/x509`: certificate chains through the compromised eMudhra intermediate CAs are rejected)
 * Reject phone number verification unless Twilio confirms the code as approved, instead of accepting any successful response
 * Ignore duplicate topics in a subscription and limit a subscription to 150 topics, so a single request cannot replay the same topic's cache over and over
 

template/gotext/GENERATED_FROM

@@ -1 +1 @@
-go1.27.1
+go1.27.3