feat: specify matrix on command line (#1675)

* added matrix option

* select the correct subset of matrix configuration after producing all the matrix configuration

* add tests

* update readme

* lint fix

* remove matrix from readme

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Co-authored-by: mergify[bot] <37929162+mergify[bot]@users.noreply.github.com>

cmd/input.go

@@ -47,6 +47,7 @@ type Input struct {
 	remoteName                         string
 	replaceGheActionWithGithubCom      []string
 	replaceGheActionTokenWithGithubCom string
+	matrix                             []string
 }
 
 func (i *Input) resolve(path string) string {