Update go to 1.23.4

Change-Id: I4a660623799dc3bb172f05a0bd5d60e4ff1c8154
Reviewed-on: https://fuchsia-review.googlesource.com/c/shac-project/shac/+/1183852
Fuchsia-Auto-Submit: Oliver Newman <olivernewman@google.com>
Reviewed-by: Ina Huh <ihuh@google.com>
Commit-Queue: Auto-Submit <auto-submit@fuchsia-infra.iam.gserviceaccount.com>

go.mod

@@ -14,9 +14,7 @@
 
 module go.fuchsia.dev/shac-project/shac
 
-go 1.22.0
-
-toolchain go1.23.4
+go 1.23.4
 
 require (
 	github.com/go-git/go-git/v5 v5.13.1

scripts/tests.sh

@@ -36,7 +36,7 @@ if ! command -v "go" > /dev/null; then
   export GOROOT="$CIPD_ROOT/go"
   echo "- Installing Go from CIPD..."
   cipd init -force "$GOROOT"
-  cipd install -log-level error -root "$GOROOT" 'infra/3pp/tools/go/${platform}' version:2@1.22.3
+  cipd install -log-level error -root "$GOROOT" 'infra/3pp/tools/go/${platform}' version:3@1.23.4
   export PATH="$GOROOT/bin:$PATH"
   echo ""
 fi