Update go.mod and vendor

vendor/github.com/moby/buildkit/source/manager.go

@@ -1,49 +0,0 @@
-package source
-
-import (
-	"context"
-	"sync"
-
-	"github.com/moby/buildkit/cache"
-	"github.com/moby/buildkit/session"
-	"github.com/pkg/errors"
-)
-
-type Source interface {
-	ID() string
-	Resolve(ctx context.Context, id Identifier, sm *session.Manager) (SourceInstance, error)
-}
-
-type SourceInstance interface {
-	CacheKey(ctx context.Context, index int) (string, bool, error)
-	Snapshot(ctx context.Context) (cache.ImmutableRef, error)
-}
-
-type Manager struct {
-	mu      sync.Mutex
-	sources map[string]Source
-}
-
-func NewManager() (*Manager, error) {
-	return &Manager{
-		sources: make(map[string]Source),
-	}, nil
-}
-
-func (sm *Manager) Register(src Source) {
-	sm.mu.Lock()
-	sm.sources[src.ID()] = src
-	sm.mu.Unlock()
-}
-
-func (sm *Manager) Resolve(ctx context.Context, id Identifier, sessM *session.Manager) (SourceInstance, error) {
-	sm.mu.Lock()
-	src, ok := sm.sources[id.ID()]
-	sm.mu.Unlock()
-
-	if !ok {
-		return nil, errors.Errorf("no handler for %s", id.ID())
-	}
-
-	return src.Resolve(ctx, id, sessM)
-}