New features

#1555 - A new store plugin has been added which simply writes a .pfx file to a folder. This was previously possible using either the CentralSsl plugin or through an installation script, but this is more convenient and easily discovered for beginners. Suggested by @Dolphyn5.
New order plugins have been added to create seperate certificate for each registerable domain or IIS site covered by the renewal target. These should still be considered beta.
@FWest98 contributed an example script for updating AD FS services.

Enhancements

#1543 - It's now possible to configure store and installation plugins of the same type more than once, e.g. if you need to run two scripts or want to store your .pem files in two different locations.
#1551 - Email notifications now include log output, requested by @Virinum.
#1530 - When creating an IIS target it's no longer required to first pick "Choose specific bindings" from the menu and then type the indices of the bindings. You can now input the indices immedately. To facilitate this, the other filter options have been given letter shortcuts. Suggested by @BrianCanFixIT.
#1529 - Instead of only logging selected requests from AcmeSharpCore, now all http requests are logged to make debugging network level issues much easier. Suggested by @MasterChiefJon.
#1528 - When showing paged lists, space is now the shortcut for going to the next page instead of enter, meaning users will be much less like accidentally trigger the default menu option at the end of the list. Suggested by @BrianCanFixIT.
Improved feedback and logging on invalid command line input.
The recursive DNS resolver used for pre-validation is now more reliable when used with delated domains.
Wildcard bindings are no longer hidden "default settings" mode, because it's no longer hardwired to use HTTP-01 validation.
Updated NuGet package dependencies.
Better handling of file system permission issues.

#1483/#1553 - Reliability improvement due to fixes for the single file application released by Microsoft in .NET Core SDK release 3.1.4.
#1524 - Route53 and Azure plugins could pick the wrong DNS zone to update if two zones overlapping names exist in the same resource group. Discovered and fixed by @rvdginste.
#1534 - The computer name would not show up in the email notification unless it was explicitly configured.
#1532 - Fix crash when creating a new binding with an IPv6 address, reported by @Conrad-T-Pino.
Azure DNS validation got various bug fixes for delegated domains (TTL decrease and creation of @ records).
The certificate cache was broken for multi-order renewals.
Enhanced/corrected various log messages.
Don't continue renewal process after one of the validations has failed.
Don't continue validation process when no matching DNS zone can be found in Azure or AWS.