CI: Move Cirrus jobs to GitHub Actions

[kinke]

No description provided.

[dlang-bot]

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[kinke]

diff:
----
 fail_compilation/test22361.d(11): Error: unable to read module `this_module_does_not_exist`
 fail_compilation/test22361.d(11):        Expected 'this_module_does_not_exist.d' or 'this_module_does_not_exist/package.d' in one of the following import paths:
 import path[0] = fail_compilation
-import path[1] = $p:druntime/import$
-import path[2] = $p:phobos$
+import path[1] = /Users/runner/work/phobos/dmd/compiler/test/../../druntime/import
+import path[2] = /Users/runner/work/phobos/dmd/compiler/test/../../../phobos

$p: seems buggy; it's using findSplitAfter, so for $p:phobos and the intermediate phobos dir here (phobos is cloned into /Users/runner/work/phobos/phobos by default), it seems to eagerly consume the first /Users/runner/work/phobos and choke on the remainder (dmd/compiler/test/../../../phobos). Sigh...

[ibuclaw]

diff:
----
 fail_compilation/test22361.d(11): Error: unable to read module `this_module_does_not_exist`
 fail_compilation/test22361.d(11):        Expected 'this_module_does_not_exist.d' or 'this_module_does_not_exist/package.d' in one of the following import paths:
 import path[0] = fail_compilation
-import path[1] = $p:druntime/import$
-import path[2] = $p:phobos$
+import path[1] = /Users/runner/work/phobos/dmd/compiler/test/../../druntime/import
+import path[2] = /Users/runner/work/phobos/dmd/compiler/test/../../../phobos

$p: seems buggy; it's using findSplitAfter, so for $p:phobos and the intermediate phobos dir here (phobos is cloned into /Users/runner/work/phobos/phobos by default), it seems to eagerly consume the first /Users/runner/work/phobos and choke on the remainder (dmd/compiler/test/../../../phobos). Sigh...

Bleh... Ok to merge now?

[kinke]

Ok to merge now?

Yep, worked around it in the 2nd commit.