Run "TZ=UTC0 admin/update-copyright".

Backporting this acked by Org maintainer Ihor Radchenko.

* lisp/org/ob-R.el (org-babel-R-associate-session):
* lisp/org/ob-clojure.el (ob-clojure-nbb-command)
(ob-clojure-cli-command):
* lisp/org/ob-core.el (org-babel-execute-src-block):
* lisp/org/ob-exp.el (org-babel-exp-code):
* lisp/org/ob-julia.el (org-babel-julia-associate-session):
* lisp/org/ob-python.el
(org-babel-python--python-util-comint-end-of-output-p):
* lisp/org/ol.el (org-insert-link):
* lisp/org/org-attach.el (org-attach):
* lisp/org/org-clock.el (org-clock-select-task):
* lisp/org/org-compat.el (fboundp):
* lisp/org/org-element-ast.el (org-element-property-raw)
(org-element-put-property, org-element-copy):
* lisp/org/org-element.el (org-element-timestamp-interpreter)
(org-element--cache-key):
* lisp/org/org-goto.el (org-goto-location):
* lisp/org/org-lint.el
(org-lint-suspicious-language-in-src-block)
(org-lint-export-option-keywords):
* lisp/org/org-macs.el (org-mks):
* lisp/org/org-persist.el: (org-persist-write:elisp):
* lisp/org/org-table.el (org-table-fedit-finish):
* lisp/org/org.el (org-entry-get-with-inheritance):
* lisp/org/ox-html.el (org-html--reference)
(org-html--build-mathjax-config, org-html-example-block):
* lisp/org/ox-latex.el (org-latex-table-row):
* lisp/org/ox.el (org-export--prune-tree)
(org-export--blindly-expand-include):
Replace use of if-let and when-let, obsolete in Emacs 31.0.50.

* lisp/org/ob-clojure.el
(ob-clojure-babashka-command, ob-clojure-nbb-command):
Account for the possibility of nil (commands absent).
* lisp/org/org.el (org-safe-remote-resources):
* lisp/org/ox-md.el (org-md-toplevel-hlevel):
* lisp/progmodes/project.el (project-vc-extra-root-markers):
Fix incorrect or invalid types.