Update go-chi/session (fixes "race" in tests) (#17031)

Update to latest go-chi/session where the NewManager causes a new
Provider instantiation instead of reconfiguring an old one.
(https://gitea.com/go-chi/session/pulls/1)

The NewManager call is now concurrency safe and would allow live
reconfiguration in future but for now this PR simply fixes an
intermittent "data-race" detected in our tests.  (See
https://drone.gitea.io/go-gitea/gitea/43900/2/14)

Related #17027
Related #1441

Signed-off-by: Andrew Thornton <art27@cantab.net>

vendor/gitea.com/go-chi/session/session.go

@@ -23,6 +23,7 @@ import (
 	"fmt"
 	"net/http"
 	"net/url"
+	"reflect"
 	"time"
 )
 
@@ -291,17 +292,34 @@ type Provider interface {
 	GC()
 }
 
-var providers = make(map[string]Provider)
+var providers = make(map[string]func() Provider)
 
 // Register registers a provider.
 func Register(name string, provider Provider) {
-	if provider == nil {
+	if reflect.TypeOf(provider).Kind() == reflect.Ptr {
+		// Pointer:
+		RegisterFn(name, func() Provider {
+			return reflect.New(reflect.ValueOf(provider).Elem().Type()).Interface().(Provider)
+		})
+		return
+	}
+
+	// Not a Pointer
+	RegisterFn(name, func() Provider {
+		return reflect.New(reflect.TypeOf(provider)).Elem().Interface().(Provider)
+	})
+}
+
+// RegisterFn registers a provider function.
+func RegisterFn(name string, providerfn func() Provider) {
+	if providerfn == nil {
 		panic("session: cannot register provider with nil value")
 	}
 	if _, dup := providers[name]; dup {
 		panic(fmt.Errorf("session: cannot register provider '%s' twice", name))
 	}
-	providers[name] = provider
+
+	providers[name] = providerfn
 }
 
 //    _____
@@ -318,12 +336,15 @@ type Manager struct {
 }
 
 // NewManager creates and returns a new session manager by given provider name and configuration.
-// It panics when given provider isn't registered.
+// It returns an error when requested provider name isn't registered.
 func NewManager(name string, opt Options) (*Manager, error) {
-	p, ok := providers[name]
+	fn, ok := providers[name]
 	if !ok {
 		return nil, fmt.Errorf("session: unknown provider '%s'(forgotten import?)", name)
 	}
+
+	p := fn()
+
 	return &Manager{p, opt}, p.Init(opt.Maxlifetime, opt.ProviderConfig)
 }