Test Emacs parts on the released 28.1 as well

[mattiase]

28.1 was recently released; snapshot tracks the development version (with some lag). Oh, and 28.1 in YAML is a number so I prefer the quotes to make it a string just in case.

[voodoos]

It is worth noting that the lint erros don't trigger CI failures. It was meant to have the log readily available for when we want to fix them:

merlin-ac.el:1:0: warning: The package summary should not end with a period.
merlin-ac.el:135:0: error: "ac-merlin-locate" doesn't start with package's prefix "merlin-ac".
merlin-cap.el:1:0: error: Package should have a ;;; Commentary section.
merlin-cap.el:1:0: warning: The package summary should not end with a period.
merlin-cap.el:1:87: warning: You should depend on (emacs "24.1") if you need lexical-binding.
merlin-cap.el:21:1: error: You should depend on (emacs "24.3") if you need `defvar-local'.
merlin-cap.el:24:1: error: You should depend on (emacs "24.3") if you need `defvar-local'.
merlin-cap.el:72:0: error: Aliases should start with the package's prefix "merlin-cap".
merlin-company.el:1:0: warning: The package summary should not end with a period.
merlin-iedit.el:1:0: error: package.el cannot parse this buffer: Search failed: ";;; merlin-iedit.el ends here"
merlin-imenu.el:1:0: error: Package should have a ;;; Commentary section.
merlin-imenu.el:1:0: warning: The package summary should not end with a period.
merlin-imenu.el:1:75: warning: You should depend on (emacs "24.1") if you need lexical-binding.
merlin-imenu.el:10:3: warning: You should include standard keywords: see the variable `finder-known-keywords'.
merlin-imenu.el:11:7: error: Package URLs should be a single HTTPS or HTTP URL.
merlin-imenu.el:14:10: error: You should depend on (emacs "24.4") if you need `subr-x'.
merlin-imenu.el:18:1: error: You should depend on (emacs "24.3") if you need `defvar-local'.
merlin-imenu.el:19:1: error: You should depend on (emacs "24.3") if you need `defvar-local'.
merlin-imenu.el:20:1: error: You should depend on (emacs "24.3") if you need `defvar-local'.
merlin-imenu.el:21:1: error: You should depend on (emacs "24.3") if you need `defvar-local'.
merlin-imenu.el:22:1: error: You should depend on (emacs "24.3") if you need `defvar-local'.
merlin-imenu.el:23:1: error: You should depend on (emacs "24.3") if you need `defvar-local'.
merlin-imenu.el:102:0: error: "merlin-use-merlin-imenu" doesn't start with package's prefix "merlin-imenu".
merlin-xref.el:1:0: warning: "Version:" or "Package-Version:" header is missing. MELPA will handle this, but other archives will not.
merlin-xref.el:1:0: error: Package should have a ;;; Commentary section.
merlin-xref.el:1:0: error: Package should have a Homepage or URL header.
merlin-xref.el:1:0: error: package.el cannot parse this buffer: Package lacks a file header
merlin-xref.el:1:7: warning: You should depend on (emacs "24.1") if you need lexical-binding.
merlin-xref.el:2:10: error: You should depend on (emacs "24.3") or the cl-lib package if you need `cl-lib'.
merlin-xref.el:3:10: error: You should depend on (emacs "25.1") if you need `xref'.
merlin-xref.el:16:1: error: You should depend on (emacs "25.1") or the cl-lib package if you need `cl-defmethod'.
merlin-xref.el:19:35: error: You should depend on (emacs "25.1") if you need `alist-get'.
merlin-xref.el:20:8: error: You should depend on (emacs "25.1") if you need `xref-make'.
merlin-xref.el:21:19: error: You should depend on (emacs "25.1") if you need `xref-make-buffer-location'.
merlin-xref.el:24:1: error: You should depend on (emacs "25.1") or the cl-lib package if you need `cl-defmethod'.
merlin-xref.el:26:16: error: You should depend on (emacs "25.1") if you need `alist-get'.
merlin-xref.el:27:15: error: You should depend on (emacs "25.1") if you need `alist-get'.
merlin-xref.el:28:16: error: You should depend on (emacs "25.1") if you need `alist-get'.
merlin-xref.el:29:15: error: You should depend on (emacs "25.1") if you need `alist-get'.
merlin-xref.el:33:15: error: You should depend on (emacs "25.1") if you need `xref-make'.
merlin-xref.el:33:31: error: You should depend on (emacs "25.1") if you need `xref-make-file-location'.
merlin-xref.el:35:1: error: You should depend on (emacs "25.1") or the cl-lib package if you need `cl-defmethod'.

We should definitely address them sometimes and then make the lint failures also fail the CI.

[mattiase]

The check.sh machinery never really worked properly but with these changes it should (I had to look up the shell parameter expansion rules for the umpteenth time).

There are still package-lint complaints but they seem to be difficult to chase away, especially when doing something nonstandard out of necessity. At least byte-compile warnings and package-lint are now controlled by different levers.

[mattiase]

As this PR has lingered unapplied, Emacs 29 has gained new warnings. The latest update takes care of them all (and fixes some doc string quoting mistakes that I overlooked the first time).

[voodoos]

Thank you @mattiase ! I will try to progress on this soon :-)