Log Message:
Update to 0.40. From the changelog:

* New/changed functionality:
  * a single DNS resolver is created for the lifetime of the program,
    rather than reinitializing the resolver for each new query.

* bugfixes:
  * fix the error message given when an invalid algorithm is
    specified in the construction of Mail::DKIM::Signer.
  * avoid Perl warning about use of an undefined value in several
    places (rt.cpan.org issue #82913).
  * speed- improved performance of parsing the message into lines
    (rt.cpan.org issue #77902). Patch by Mark Martinec.
  * fix DNS queries to use the correct method (txtdata) of Net::DNS
    (rt.cpan.org issue #83170). Patch by Mark Martinec.
  * fix issue with getting wrong error codes when q= tag is empty
    (issue #3011005)
  * anti-abuse- prevent a message with thousands of signatures from
    thrashing the whole computer (issue #3010997)
  * memory usage- significantly reduced memory footprint for
    processing a message with a large header and many signatures
  * fix error message given when no KeyFile has been specified
    (issue #1889690)

* API changes:
  * global subroutines resolver() or enable_EDNS0() in module
    Mail::DKIM::DNS can be called to specify non-default options
    to Net::DNS::Resolver (see also rt.cpan.org issue #80425).
  * the Canonicalization::finish_header() method now expects a
    argument to be passed to it. In the unusual case that you are
    using this method from your own code, please update your code.