Fix path for local node12 actions (#371)

Fixes #185

Signed-off-by: Javier Romero <root@jromero.codes>

pkg/runner/testdata/actions/node12/action.yml

@@ -0,0 +1,13 @@
+name: 'Hello World'
+description: 'Greet someone and record the time'
+inputs:
+  who-to-greet:  # id of input
+    description: 'Who to greet'
+    required: true
+    default: 'World'
+outputs:
+  time: # id of output
+    description: 'The time we greeted you'
+runs:
+  using: 'node12'
+  main: 'dist/index.js'