Parse secret inputs in reusable workflows (#41)

Secrets can be passed to reusable workflows, either explicitly by key or
implicitly by `inherit`:

https://docs.github.com/en/actions/using-workflows/reusing-workflows#using-inputs-and-secrets-in-a-reusable-workflow

Reviewed-on: https://gitea.com/gitea/act/pulls/41
Reviewed-by: Jason Song <i@wolfogre.com>
Co-authored-by: Galen Abell <galen@galenabell.com>
Co-committed-by: Galen Abell <galen@galenabell.com>

act/jobparser/jobparser_test.go

@@ -37,6 +37,11 @@ func TestParse(t *testing.T) {
 			options: nil,
 			wantErr: false,
 		},
+		{
+			name:    "has_secrets",
+			options: nil,
+			wantErr: false,
+		},
 	}
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {