chore: Bump to Go version 1.21.3 (#3820)

Go 1.21.3 fixes a vulnerability in the HTTP stack where a malicious
HTTP/2 client which rapidly creates requests and immediately resets them
can cause excessive server resource consumption.

More detail in https://groups.google.com/g/golang-announce/c/iNNxDTCjZvo

Co-authored-by: Hugo <hugoamvieira@users.noreply.github.com>

.go-version

@@ -1 +1 @@
-1.21.1
+1.21.3