upgrade deps; rewrite smtp session

vendor/github.com/getsentry/sentry-go/stacktrace_below_go1.20.go

@@ -0,0 +1,15 @@
+//go:build !go1.20
+
+package sentry
+
+import "strings"
+
+func isCompilerGeneratedSymbol(name string) bool {
+	// In versions of Go below 1.20 a prefix of "type." and "go." is a
+	// compiler-generated symbol that doesn't belong to any package.
+	// See variable reservedimports in cmd/compile/internal/gc/subr.go
+	if strings.HasPrefix(name, "go.") || strings.HasPrefix(name, "type.") {
+		return true
+	}
+	return false
+}