Singular credit_card controller name changed to plural
Stop nil checking on safe_append=

ERB compiler guarantees safe_append= will be called with a string, so
nil checks don't make sense.  Anything else calling this method should
check for nil themselves before calling
Pare down and simplify Active Job's rake tasks
Tighten up AJ::Arguments and its tests

* Disallow deserialization of non-primitive objects
* Broaden coverage; remove superfluous tests
simplify test_adapter
Merge pull request #16918 from kiuru/master

Singular credit_card controller name changed to plural [ci skip]
Merge pull request #16920 from seuros/aj

simplify test_adapter
handle <%== nil %> cases

This is much less common than string literal appends, so add a special
case method for it.  Maybe fixes bug reported by @jeremy on 97ef636191933f1d4abc92fc10871e6d1195285c
Add `test:jobs` task
Merge pull request #16922 from y-yagi/add_test_jobs_task

Add test jobs task
add implementation of respond_to? for ActiveSupport::Duration
Merge pull request #16574 from lsylvester/duration-respond_to

add implementation of respond_to? for ActiveSupport::Duration
Methods for ActiveSupport::Duration parsing from and output to ISO 8601

This is required for PostgreSQL interval datatype support and its convertion from and to ActiveSupport::Duration.
Also it may be useful for others. Some parts of code and tests is taken from ISO8601 gem by Arnau Siches (@arnau).
Fix notes
Introduced separate ISO 8601 duration parser, related and unrelated fixes