feat: add a deprecation warning when running Taskfiles with a v2 schema

setup.go

@@ -250,7 +250,11 @@ func (e *Executor) doVersionChecks() error {
 	*v = *e.Taskfile.Version
 
 	if v.LessThan(taskfile.V2) {
-		return fmt.Errorf(`task: Taskfile versions prior to v2 are not supported anymore`)
+		return fmt.Errorf(`task: version 1 schemas are no longer supported`)
+	}
+
+	if v.LessThan(taskfile.V3) {
+		e.Logger.Outf(logger.Yellow, "task: version 2 schemas are deprecated and will be removed in a future release\nSee https://github.com/go-task/task/issues/1197 for more details\n")
 	}
 
 	// consider as equal to the greater version if round

task_test.go

@@ -1360,15 +1360,27 @@ func TestDynamicVariablesShouldRunOnTheTaskDir(t *testing.T) {
 	tt.Run(t)
 }
 
-func TestDisplaysErrorOnUnsupportedVersion(t *testing.T) {
+func TestDisplaysErrorOnVersion1Schema(t *testing.T) {
 	e := task.Executor{
 		Dir:    "testdata/version/v1",
 		Stdout: io.Discard,
 		Stderr: io.Discard,
 	}
 	err := e.Setup()
 	require.Error(t, err)
-	assert.Equal(t, "task: Taskfile versions prior to v2 are not supported anymore", err.Error())
+	assert.Equal(t, "task: version 1 schemas are no longer supported", err.Error())
+}
+
+func TestDisplaysWarningOnVersion2Schema(t *testing.T) {
+	var buff bytes.Buffer
+	e := task.Executor{
+		Dir:    "testdata/version/v2",
+		Stdout: &buff,
+		Stderr: io.Discard,
+	}
+	err := e.Setup()
+	require.NoError(t, err)
+	assert.Equal(t, "task: version 2 schemas are deprecated and will be removed in a future release\nSee https://github.com/go-task/task/issues/1197 for more details\n", buff.String())
 }
 
 func TestShortTaskNotation(t *testing.T) {