Avoid using log.Fatal in pkg/* (#39)

Follow https://github.com/nektos/act/pull/1705

Reviewed-on: https://gitea.com/gitea/act/pulls/39
Reviewed-by: Lunny Xiao <xiaolunwen@gmail.com>
Co-authored-by: Jason Song <i@wolfogre.com>
Co-committed-by: Jason Song <i@wolfogre.com>

pkg/runner/runner.go

@@ -7,11 +7,11 @@ import (
 	"os"
 	"time"
 
-	log "github.com/sirupsen/logrus"
-
 	"github.com/nektos/act/pkg/common"
 	"github.com/nektos/act/pkg/container"
 	"github.com/nektos/act/pkg/model"
+
+	log "github.com/sirupsen/logrus"
 )
 
 // Runner provides capabilities to run GitHub actions
@@ -136,7 +136,11 @@ func (runner *runnerImpl) NewPlanExecutor(plan *model.Plan) common.Executor {
 						log.Errorf("Error while evaluating matrix: %v", err)
 					}
 				}
-				matrixes := job.GetMatrixes()
+				matrixes, err := job.GetMatrixes()
+				if err != nil {
+					log.Errorf("Error while get job's matrix: %v", err)
+					// fall back to empty matrixes
+				}
 				maxParallel := 4
 				if job.Strategy != nil {
 					maxParallel = job.Strategy.MaxParallel