Keep the order of jobs in the workflow file when parsing (#33)

Keep the order of jobs in the workflow file when parsing, and it will make it possible for Gitea to show jobs in the original order on UI.

Reviewed-on: https://gitea.com/gitea/act/pulls/33
Reviewed-by: Lunny Xiao <xiaolunwen@gmail.com>

act/jobparser/testdata/multiple_jobs.in.yaml

@@ -1,5 +1,9 @@
 name: test
 jobs:
+  zzz:
+    runs-on: linux
+    steps:
+      - run: echo zzz
   job1:
     runs-on: linux
     steps:
@@ -11,4 +15,8 @@ jobs:
   job3:
     runs-on: linux
     steps:
-      - run: uname -a && go version
+      - run: uname -a && go version
+  aaa:
+    runs-on: linux
+    steps:
+      - run: uname -a && go version

act/jobparser/testdata/multiple_jobs.out.yaml

@@ -1,4 +1,12 @@
 name: test
+jobs:
+  zzz:
+    name: zzz
+    runs-on: linux
+    steps:
+      - run: echo zzz
+---
+name: test
 jobs:
   job1:
     name: job1
@@ -21,3 +29,11 @@ jobs:
     runs-on: linux
     steps:
       - run: uname -a && go version
+---
+name: test
+jobs:
+  aaa:
+    name: aaa
+    runs-on: linux
+    steps:
+      - run: uname -a && go version