deps: update go-plugin to 1.6.2 (#24265)

During allocation recovery, the go-plugin reattachment workflow checks to see if
the PID we stored in client state is still running. If so, we try to connect to
that process. If that fails, we kill the process under the presumption it's not
working. But during reattachment we don't know that the PID we have is still
valid. Which means that the process we're trying to attach to may have exited
and a different process has spawned with the same PID. This results in some
unrelated process getting silently killed.

Update go-plugin to 1.6.2, which includes a bug fix so we do not kill the
process.

Fixes: https://github.com/hashicorp/nomad/issues/23969

plugins/drivers/testutils/testing.go

@@ -9,6 +9,7 @@ import (
 	"os"
 	"path/filepath"
 	"runtime"
+	"testing"
 	"time"
 
 	hclog "github.com/hashicorp/go-hclog"
@@ -25,7 +26,6 @@ import (
 	"github.com/hashicorp/nomad/plugins/drivers"
 	"github.com/hashicorp/nomad/plugins/drivers/fsisolation"
 	"github.com/hashicorp/nomad/plugins/shared/hclspec"
-	testing "github.com/mitchellh/go-testing-interface"
 	"github.com/shoenig/test/must"
 )
 
@@ -33,7 +33,7 @@ type DriverHarness struct {
 	drivers.DriverPlugin
 	client *plugin.GRPCClient
 	server *plugin.GRPCServer
-	t      testing.T
+	t      *testing.T
 	logger hclog.Logger
 	impl   drivers.DriverPlugin
 	cgroup string
@@ -42,7 +42,7 @@ type DriverHarness struct {
 func (h *DriverHarness) Impl() drivers.DriverPlugin {
 	return h.impl
 }
-func NewDriverHarness(t testing.T, d drivers.DriverPlugin) *DriverHarness {
+func NewDriverHarness(t *testing.T, d drivers.DriverPlugin) *DriverHarness {
 	logger := testlog.HCLogger(t).Named("driver_harness")
 	pd := drivers.NewDriverPlugin(d, logger)