fix #108 - ensure container names are unique for matrix runs

.actrc

@@ -1 +1 @@
--P ubuntu-latest=nektos/act-environments-ubuntu:18.04 
+-P ubuntu-latest=nektos/act-environments-ubuntu:18.04

pkg/runner/runner.go

@@ -63,7 +63,7 @@ func (runner *runnerImpl) NewPlanExecutor(plan *model.Plan) common.Executor {
 
 			for i, matrix := range matrixes {
 				rc := runner.newRunContext(run, matrix)
-				if len(matrix) > 1 {
+				if len(matrixes) > 1 {
 					rc.Name = fmt.Sprintf("%s-%d", rc.Name, i+1)
 				}
 				if len(rc.String()) > maxJobNameLen {

pkg/runner/testdata/matrix/push.yml

@@ -13,3 +13,13 @@ jobs:
       matrix:
         os: [ubuntu-18.04, macos-latest]
         node: [4, 6, 8, 10]
+
+  test:
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        node: [8.x, 10.x, 12.x, 13.x]
+    steps:
+      - run: echo ${NODE_VERSION} | grep ${{ matrix.node }}
+        env:
+          NODE_VERSION: ${{ matrix.node }}