feat(task): dependencies (#26467)

This commit adds support for "dependencies" in `deno task` subcommand:
```jsonc
{
    "tasks": {
        "build": "deno run -RW build.ts",
        "generate": "deno run -RW generate.ts",
        "serve": {
            "command": "deno run -RN server.ts",
            "dependencies": ["build", "generate"]
        }
    }
}
```
Executing `deno task serve` will first execute `build` and `generate`
tasks (in parallel) and once both complete the `serve` task will be executed.

Number of tasks run in parallel is equal to the no of cores on the
machine, and respects `DENO_JOBS` env var if one is specified.

Part of https://github.com/denoland/deno/issues/26462

---------

Co-authored-by: Bartek Iwańczuk <biwanczuk@gmail.com>
Co-authored-by: Marvin Hagemeister <marvin@deno.com>

1 files changed, 4 insertions, 0 deletions

diff --git a/tests/specs/task/dependencies/util.js b/tests/specs/task/dependencies/util.js
new file mode 100644
index 000000000..9579eb9c9
--- /dev/null
+++ b/tests/specs/task/dependencies/util.js
@@ -0,0 +1,4 @@
+export async function randomTimeout(min, max) {
+  const timeout = Math.floor(Math.random() * (max - min + 1) + min);
+  return new Promise((resolve) => setTimeout(resolve, timeout));
+}