Add containerdVersion flag

Add version flag that only prints the static version for the binary.

This commit does not include build details for containers since
Makefile does not build them.

Closes #8

Signed-off-by: Christopher M. Luciano <cmluciano@us.ibm.com>

pkg/version/version_test.go

@@ -0,0 +1,33 @@
+/*
+Copyright 2017 The Kubernetes Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package version
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestValidateSemver(t *testing.T) {
+	err := validateSemver("UNKNOWN")
+	assert := assert.New(t)
+	assert.NotNil(err)
+	err = validateSemver("0.0.0-1-gdf6a1cc-dirty")
+	assert.Nil(err)
+	err = validateSemver(criContainerdVersion)
+	assert.Nil(err)
+}