fix: allow expressions in step and job uses: (#766)

Resolves forgejo/runner#764

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<!--URL:https://code.forgejo.org/forgejo/runner-->
- bug fixes
  - [PR](https://code.forgejo.org/forgejo/runner/pulls/766): <!--number 766 --><!--line 0 --><!--description Zml4OiBhbGxvdyBleHByZXNzaW9ucyBpbiBzdGVwIGFuZCBqb2IgdXNlczo=-->fix: allow expressions in step and job uses:<!--description-->
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Reviewed-on: https://code.forgejo.org/forgejo/runner/pulls/766
Reviewed-by: Michael Kriese <michael.kriese@gmx.de>
Co-authored-by: Earl Warren <contact@earl-warren.org>
Co-committed-by: Earl Warren <contact@earl-warren.org>

act/schema/schema_test.go

@@ -60,6 +60,7 @@ jobs:
     steps:
     - run: exit 0
       if: success() || failure() || always()
+    - uses: https://${{ secrets.PAT }}@example.com/action/here@v1
 `), &node)
 	if !assert.NoError(t, err) {
 		return
@@ -107,7 +108,7 @@ jobs:
     runs-on: ubuntu-latest
     container:
       image: code.forgejo.org/oci/node:22-bookworm
-    uses: ./.github/workflows/build.yaml
+    uses: ./.forgejo/workflows/${{ vars.PATHNAME }}
     with:
       STAGE: dev
     secrets:

act/schema/workflow_schema.json

@@ -1469,7 +1469,7 @@
           },
           "uses": {
             "description": "The location and version of a reusable workflow file to run as a job. Use one of the following formats:\n\n* `{owner}/{repo}/.github/workflows/{filename}@{ref}` for reusable workflows in public and private repositories.\n* `./.github/workflows/{filename}` for reusable workflows in the same repository.\n\n{ref} can be a SHA, a release tag, or a branch name. Using the commit SHA is the safest for stability and security.",
-            "type": "non-empty-string",
+            "type": "job-uses",
             "required": true
           },
           "runs-on": {
@@ -1798,11 +1798,46 @@
       }
     },
     "step-uses": {
+      "context": [
+        "forge",
+        "github",
+        "inputs",
+        "vars",
+        "needs",
+        "strategy",
+        "matrix",
+        "secrets",
+        "steps",
+        "job",
+        "runner",
+        "env",
+        "hashFiles(1,255)"
+      ],
       "description": "Selects an action to run as part of a step in your job. An action is a reusable unit of code. You can use an action defined in the same repository as the workflow, a public repository, or in a published Docker container image.",
       "string": {
         "require-non-empty": true
       }
     },
+    "job-uses": {
+      "context": [
+        "forge",
+        "github",
+        "inputs",
+        "vars",
+        "needs",
+        "strategy",
+        "matrix",
+        "secrets",
+        "steps",
+        "job",
+        "runner",
+        "env",
+        "hashFiles(1,255)"
+      ],
+      "string": {
+        "require-non-empty": true
+      }
+    },
     "step-continue-on-error": {
       "context": [
         "forge",