refactor: NewWorkflowPlanner (#648)

feat: add flag `--no-recurse` to disable recursion when reading workflows from directories
feat: added more tests to `TestPlanner`, renamed `TestJobFileInfo` to more appropriate name `WorkflowPlanTest`
style: changed error message to lowercase, added single quotes for better visibility

Co-authored-by: Casey Lee <cplee@nektos.com>

pkg/model/testdata/invalid-job-name/invalid-1.yml

@@ -1,4 +1,4 @@
-name: invalid-job-name
+name: invalid-job-name-1
 on: push
 
 jobs:

pkg/model/testdata/invalid-job-name/invalid-2.yml

@@ -0,0 +1,8 @@
+name: invalid-job-name-2
+on: push
+
+jobs:
+  1234invalid-JOB-Name-v123-docker_hub:
+    runs-on: ubuntu-latest
+    steps:
+      - run: echo hi

pkg/model/testdata/invalid-job-name/valid-1.yml

@@ -0,0 +1,8 @@
+name: valid-job-name-1
+on: push
+
+jobs:
+  valid-JOB-Name-v123-docker_hub:
+    runs-on: ubuntu-latest
+    steps:
+      - run: echo hi

pkg/model/testdata/invalid-job-name/valid-2.yml

@@ -0,0 +1,8 @@
+name: valid-job-name-2
+on: push
+
+jobs:
+  ___valid-JOB-Name-v123-docker_hub:
+    runs-on: ubuntu-latest
+    steps:
+      - run: echo hi