fix(go): support 1.16

resolves #428

src/segment_golang.go

@@ -17,7 +17,7 @@ func (g *golang) init(props *properties, env environmentInfo) {
 			{
 				executable: "go",
 				args:       []string{"version"},
-				regex:      `(?:go(?P<version>((?P<major>[0-9]+).(?P<minor>[0-9]+).(?P<patch>[0-9]+))))`,
+				regex:      `(?:go(?P<version>((?P<major>[0-9]+).(?P<minor>[0-9]+)(.(?P<patch>[0-9]+))?)))`,
 			},
 		},
 		versionURLTemplate: "[%s](https://golang.org/doc/go%s.%s)",

src/segment_golang_test.go

@@ -0,0 +1,34 @@
+package main
+
+import (
+	"fmt"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestGolang(t *testing.T) {
+	cases := []struct {
+		Case           string
+		ExpectedString string
+		Version        string
+	}{
+		{Case: "Go 1.15", ExpectedString: "1.15.8", Version: "go version go1.15.8 darwin/amd64"},
+		{Case: "Go 1.16", ExpectedString: "1.16", Version: "go version go1.16 darwin/amd64"},
+	}
+	for _, tc := range cases {
+		env := new(MockedEnvironment)
+		env.On("hasCommand", "go").Return(true)
+		env.On("runCommand", "go", []string{"version"}).Return(tc.Version, nil)
+		env.On("hasFiles", "*.go").Return(true)
+		props := &properties{
+			values: map[Property]interface{}{
+				DisplayVersion: true,
+			},
+		}
+		g := &golang{}
+		g.init(props, env)
+		assert.True(t, g.enabled(), fmt.Sprintf("Failed in case: %s", tc.Case))
+		assert.Equal(t, tc.ExpectedString, g.string(), fmt.Sprintf("Failed in case: %s", tc.Case))
+	}
+}