Add container version getter (#581)

container/container.go

@@ -552,3 +552,10 @@ func (x Container) AssertID(id cid.ID) bool {
 
 	return id2.Equals(id)
 }
+
+// Version returns the NeoFS API version this container was created with.
+func (x Container) Version() version.Version {
+	var v version.Version
+	_ = v.ReadFromV2(*x.v2.GetVersion()) // No, this can't fail for x.
+	return v
+}

container/container_test.go

@@ -48,6 +48,9 @@ func TestContainer_Init(t *testing.T) {
 
 	val.Init()
 
+	var ver = val.Version()
+	require.Equal(t, version.Current(), ver)
+
 	var msg v2container.Container
 	val.WriteToV2(&msg)
 
@@ -60,7 +63,6 @@ func TestContainer_Init(t *testing.T) {
 	verV2 := msg.GetVersion()
 	require.NotNil(t, verV2)
 
-	var ver version.Version
 	require.NoError(t, ver.ReadFromV2(*verV2))
 
 	require.Equal(t, version.Current(), ver)

version/version.go

@@ -18,7 +18,7 @@ import (
 //	_ = Version(refs.Version{}) // not recommended
 type Version refs.Version
 
-const sdkMjr, sdkMnr = 2, 13
+const sdkMjr, sdkMnr = 2, 16
 
 // Current returns Version instance that initialized to the
 // latest supported NeoFS API revision number in SDK.