Fix broken "How to contribute" link

Also, make 'require()' function not fail by default.
The only case where we really need to fail is when 'kramdown' parser is
not specified. This is a highly unlikely scenario, tbh (because
arguments to `lesson_check.py` are set in the Makefile), but we can
think about reworking/optimizing this part later.

lesson_check.py: report check status at the end

util.py: load_yaml: Don't fail when it's not necessary

lesson_check.py: fix error message for the 'defaults' check

lesson_check.py: use proper regex for matching episode files

1. Read `config.yml` file only once and store the contents in a global
   variable `CONFIG`. We're currently reading this file twice.
2. Detect lesson life cycle in `main` instead of making `check_config`
   return it.
3. Replace `using_remote_theme` function with a single test that checks
   that `remote_theme` keyword is present in `_config.yml`
4. CheckEpisode class: `check` method: move "remote theme test" inside the `check_reference_inclusion`.
5. main: mvoe "remote theme test" inside the `read_references`

lesson-check.py: read `config.yml` only once

Port of carpentries/instructor-training@f488d24

Co-authored-by: François Michonneau <francois.michonneau@gmail.com>

Co-authored-by: François Michonneau <francois.michonneau@gmail.com>

Port of carpentries/instructor-training@dc1b52a

Co-authored-by: maneesha sane <maneeshasane@gmail.com>

Co-authored-by: maneesha sane <maneeshasane@gmail.com>

Co-authored-by: Toby Hodges <tbyhdgs@gmail.com>

Printing to paper or PDF via the browser would invoke the @media print CSS query. It is useful to show all solution while doing so

update e-mail address

Workaround to a CSS resize blur rendering problem affecting Google Chrome/Chromium
when the resolution of the image is larger than the image view

See https://stackoverflow.com/a/69156216 and
carpentries-incubator/jekyll-pages-novice#274 for additional context.

…pages"

This reverts commit cb78403.

I used the conversion for 1px = 0.0625em based on a default 16pt font

This will address part of carpentries/styles#630

add new steps to transition lessons to Workbench

1. The transtion headers will now have a button that can close them
   (though its not permenent)
2. The third step of the transition will no longer be coded into the
   yaml here because the third step of the transition will use the
   workbench version as the default version. This means that no redirect
   will be needed.
3. All transition dates will be specified
4. Language has been updated to not refer to "Jekyll" as it may not be
   immediately obvious that Jekyll was used to build the site.

modify transition workflow/variables

This will fix #641

this will fix #642

Fix workflows 641

update beta phase target