feature: Add support for github action variables (#1833)

* feature: Add support for github action variables

* add --var flag for github variables

* unitests: Updated unittests to cover vars context.

* Remove syntax extension for vars and correct unit tests

* Update pkg/runner/expression.go

Co-authored-by: ChristopherHX <christopher.homberger@web.de>

---------

Co-authored-by: kuanyong-wong-partior <kuanyong.wong@partior.com>
Co-authored-by: ChristopherHX <christopher.homberger@web.de>

cmd/input.go

@@ -16,6 +16,7 @@ type Input struct {
 	reuseContainers                    bool
 	bindWorkdir                        bool
 	secrets                            []string
+	vars                               []string
 	envs                               []string
 	inputs                             []string
 	platforms                          []string
@@ -26,6 +27,7 @@ type Input struct {
 	envfile                            string
 	inputfile                          string
 	secretfile                         string
+	varfile                            string
 	insecureSecrets                    bool
 	defaultBranch                      string
 	privileged                         bool
@@ -78,6 +80,10 @@ func (i *Input) Secretfile() string {
 	return i.resolve(i.secretfile)
 }
 
+func (i *Input) Varfile() string {
+	return i.resolve(i.varfile)
+}
+
 // Workdir returns path to workdir
 func (i *Input) Workdir() string {
 	return i.resolve(".")