move cache to sync package

rollback indexer map
use sync.pool for cache entries
add tests for cache
remove main locks from nrwmutex and use sync.map and sync.pool instead
bump dockerfile go version

proxy/pkg/middleware/oidc_auth.go

@@ -10,9 +10,9 @@ import (
 	"github.com/dgrijalva/jwt-go"
 
 	gOidc "github.com/coreos/go-oidc"
-	"github.com/owncloud/ocis/ocis-pkg/cache"
 	"github.com/owncloud/ocis/ocis-pkg/log"
 	"github.com/owncloud/ocis/ocis-pkg/oidc"
+	"github.com/owncloud/ocis/ocis-pkg/sync"
 	"golang.org/x/oauth2"
 )
 
@@ -24,7 +24,7 @@ type OIDCProvider interface {
 // OIDCAuth provides a middleware to check access secured by a static token.
 func OIDCAuth(optionSetters ...Option) func(next http.Handler) http.Handler {
 	options := newOptions(optionSetters...)
-	tokenCache := cache.NewCache(options.UserinfoCacheSize)
+	tokenCache := sync.NewCache(options.UserinfoCacheSize)
 
 	h := oidcAuth{
 		logger:        options.Logger,
@@ -74,7 +74,7 @@ type oidcAuth struct {
 	providerFunc  func() (OIDCProvider, error)
 	httpClient    *http.Client
 	oidcIss       string
-	tokenCache    *cache.Cache
+	tokenCache    *sync.Cache
 	tokenCacheTTL time.Duration
 }