cmd/govulncheck/integration: update go version in Dockerfile

Otherwise, the integration tests fails since we've recently made the
change to require go1.23.0 as the minimum version for vuln repo.

Change-Id: I68c3e06303a5b202c850c2655f636e3444ceba5f
Reviewed-on: https://go-review.googlesource.com/c/vuln/+/650295
Reviewed-by: Dmitri Shuralyov <dmitshur@golang.org>
Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>
Commit-Queue: Zvonimir Pavlinovic <zpavlinovic@google.com>
Auto-Submit: Zvonimir Pavlinovic <zpavlinovic@google.com>
TryBot-Bypass: Zvonimir Pavlinovic <zpavlinovic@google.com>

cmd/govulncheck/integration/Dockerfile

diff --git a/cmd/govulncheck/integration/Dockerfile b/cmd/govulncheck/integration/Dockerfile
index c423d2e..2c7bcb8 100644
--- a/cmd/govulncheck/integration/Dockerfile
+++ b/cmd/govulncheck/integration/Dockerfile
@@ -1,4 +1,4 @@
-FROM golang:1.22.3-alpine
+FROM golang:1.23.0-alpine
 
 # This Dockerfile sets up an image for repeated integration testing.
 # This assumes the build context, i.e., CWD is vuln/