use kebab case for transition step variable name

Author: fmichonneau

_includes/lesson_footer.html

@@ -28,7 +28,7 @@
 	{% endif %}
     </div>
     <div class="col-md-6 help-links" align="right">
-        {% if site.life_cycle contains 'transition_step' %}
+        {% if site.life_cycle contains 'transition-step' %}
         <a href="{{repo_url}}">Edit on GitHub</a>
         {% elsif page.source == "Rmd" %}
 	<a href="{{repo_url}}/edit/{{ default_branch }}/{{page.path|replace: "_episodes", "_episodes_rmd" | replace: ".md", ".Rmd"}}" data-checker-ignore>Edit on GitHub</a>

_includes/life_cycle.html

@@ -34,13 +34,13 @@
 
 {% comment %}
 Below we cover the 3 phases of lesson transition towards the Carpentries Workbench:
-- transition_step_1 (`transition_url` variable needed): we indicate that there
+- transition-step-1 (`transition_url` variable needed): we indicate that there
 is a new version of the lesson that is available for testing, and that it will be deprecated in the future.
-- transition_step_2 (`transition_url` and `transition_date` variables needed): we indicate that a new version of the lesson is avaiable with a deprecation date.
-- transition_step_3 (`transition_url` variable needed): the lesson if fully deprecated, and a redirect is set up to the new URL
+- transition-step-2 (`transition_url` and `transition_date` variables needed): we indicate that a new version of the lesson is avaiable with a deprecation date.
+- transition-step-3 (`transition_url` variable needed): the lesson if fully deprecated, and a redirect is set up to the new URL
 {% endcomment %}
 
-{% elsif site.life_cycle == "transition_step_1" %}
+{% elsif site.life_cycle == "transition-step-1" %}
 {% include check_transition_variables.html need_transition_date = 'false' %}
 
 <div class="alert alert-warning life-cycle">
@@ -49,15 +49,15 @@
   This lesson will become deprecated in the near future.
 </div>
 
-{% elsif site.life_cycle == "transition_step_2" %}
+{% elsif site.life_cycle == "transition-step-2" %}
 {% include check_transition_variables.html need_transition_date = 'true' %}
 
 <div class="alert alert-danger life-cycle">
   A newer version of this lesson is available from: <a href="{{ site.transition_url }}">{{ site.transition_url }}</a>.
   This lesson will become deprecated on {{ site.transition_date }}.
 </div>
 
-{% elsif site.life_cycle == "transition_step_3" %}
+{% elsif site.life_cycle == "transition-step-3" %}
 {% include check_transition_variables.html need_transition_date = 'false' %}
 
 <div class="alert alert-danger life-cycle">

_includes/navbar.html

@@ -94,7 +94,7 @@
 
 	{% comment %} Always show license. {% endcomment %}
         <li><a href="{{ relative_root_path }}{% link LICENSE.md %}">License</a></li>
-        {% if site.life_cycle contains 'transition_step' %}
+        {% if site.life_cycle contains 'transition-step' %}
         <li><a href="{{repo_url}}">Improve this page <span class="glyphicon glyphicon-pencil" aria-hidden="true"></span></a></li>
         {% elsif page.source == "Rmd" %}
 	<li><a href="{{repo_url}}/edit/{{ default_branch }}/{{page.path|replace: "_episodes", "_episodes_rmd" | replace: ".md", ".Rmd"}}" data-checker-ignore>Improve this page <span class="glyphicon glyphicon-pencil" aria-hidden="true"></span></a></li>

_layouts/base.html

@@ -23,7 +23,7 @@
 
     {% include favicons.html %}
 
-    {% if site.life_cycle == 'transition_step_3' %}
+    {% if site.life_cycle == 'transition-step-3' %}
     <meta http-equiv="refresh" content="0; url={{ site.transition_url }}" />
     {% endif %}
 

bin/boilerplate/_config.yml

@@ -19,18 +19,18 @@ title: "Lesson Title"
 #
 # Lessons that are going through the transition to the
 # Carpentries Workbench will go through 3 steps:
-# 'transition_step_1': notice indicating a new version
-# 'transition_step_2': notice encouraging to use new version
-# 'transition_step_3': notice indicating the lesson is deprecated,
+# 'transition-step-1': notice indicating a new version
+# 'transition-step-2': notice encouraging to use new version
+# 'transition-step-3': notice indicating the lesson is deprecated,
 #                      with automated redirect
 life_cycle: "pre-alpha"
 
-# For lessons in the life stages in 'transition_step_1' or later:
+# For lessons in the life stages in 'transition-step-1' or later:
 # - 'transition_url' holds the URL for the version of the lesson that
 #    uses the Workbench (needed for all 3 steps)
 # - 'transition_date' (in yyyy-mm-dd format) is the date when the lesson
 #    will transition to being deprecated. The date only needs to be decided
-#    when the lesson is in 'transition_step_2'.
+#    when the lesson is in 'transition-step-2'.
 transition_url:
 transition_date: