CI: skip gpgme-config test on Arch

gpgme has decided that config-tool is bad, which makes sense. They've
also decided that they will only install theirs, if gpg-error also
installs one, which is a bit... confusing. Anyway, it's impossible to
know whether it should or should not exist, so just accept that this
test is ready to be skipped on distros that currently no longer have
this ancient config-tool script.

Victory is within reach!

test cases/frameworks/27 gpgme/test.json

@@ -1,3 +1,3 @@
 {
-  "skip_on_jobname": ["azure", "cygwin", "macos", "msys2"]
+  "skip_on_jobname": ["azure", "cygwin", "macos", "msys2", "linux-arch"]
 }