Add ubuntu-slim and update runner labels (#256)

* Add ubuntu-slim and update runner labels

- Add ubuntu-slim runner (new 1-vCPU Linux runner)
- Add ubuntu-24.04 (current LTS)
- Update macOS runners to current versions (15, 14, 13)
- Remove deprecated runners (ubuntu-18.04, macos-12, macos-11, macos-10.15)
- Update tests to reflect new runner count

Fixes #255

* Remove macos-13 runner label

Per internal confirmation, macos-13 should not be included in the
suggested runner labels.

languageservice/src/value-providers/default.ts

@@ -6,16 +6,16 @@ import {stringsToValues} from "./strings-to-values";
 
 export const DEFAULT_RUNNER_LABELS = [
   "ubuntu-latest",
+  "ubuntu-24.04",
   "ubuntu-22.04",
   "ubuntu-20.04",
-  "ubuntu-18.04",
+  "ubuntu-slim",
   "windows-latest",
   "windows-2022",
   "windows-2019",
   "macos-latest",
-  "macos-12",
-  "macos-11",
-  "macos-10.15",
+  "macos-15",
+  "macos-14",
   "self-hosted"
 ];