docs(openapi): auto-bump OpenAPI version on merge to master when spec changes (#2289)

### Description

Adds a GitHub Actions workflow that automatically bumps the
`info.version` field in the OpenAPI specification whenever `apify-api/`
files are changed and merged to master.


<!-- CURSOR_SUMMARY -->
---

> [!NOTE]
> **Low Risk**
> Low risk: documentation/spec and CI automation only, with the main
risk being noisy extra commits or workflow misfires on `master` pushes
affecting repo history.
> 
> **Overview**
> Adds a GitHub Actions workflow (`bump-openapi-version.yaml`) that, on
pushes to `master` affecting `apify-api/**`, overwrites
`apify-api/openapi/components/version.yaml` with a fresh UTC timestamp
and commits it back to the repo.
> 
> Updates `apify-api/openapi/openapi.yaml` to source `info.version` from
the new `components/version.yaml` via `$ref`, so the published OpenAPI
spec version tracks these automated bumps.
> 
> <sup>Written by [Cursor
Bugbot](https://cursor.com/dashboard?tab=bugbot) for commit
5d6f5c8. Configure
[here](https://cursor.com/dashboard?tab=bugbot).</sup>
<!-- /CURSOR_SUMMARY -->

---------

Co-authored-by: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: Pijukatel

.github/workflows/bump-openapi-version.yaml

@@ -0,0 +1,29 @@
+name: Bump OpenAPI version
+
+on:
+    push:
+        branches:
+            - master
+        paths:
+            - 'apify-api/**'
+
+jobs:
+    bump-version:
+        name: Bump OpenAPI version
+        runs-on: ubuntu-latest
+        permissions:
+            contents: write
+
+        steps:
+            - uses: actions/checkout@v6
+
+            - name: Bump OpenAPI version
+              run: echo "v2-$(date -u +%Y-%m-%dT%H%M%SZ)" > apify-api/openapi/components/version.yaml
+
+            - name: Commit changes
+              id: commit
+              uses: EndBug/add-and-commit@v9
+              with:
+                  author_name: github-actions[bot]
+                  author_email: 41898282+github-actions[bot]@users.noreply.github.com
+                  message: "chore(openapi): Update OpenAPI version [skip ci]"

apify-api/openapi/components/version.yaml

@@ -0,0 +1 @@
+v2-2026-02-27T074438Z

apify-api/openapi/openapi.yaml

@@ -474,7 +474,8 @@ info:
     - `~resourcename` - for this, you need to use an API token, and the
     `resourcename` refers to a resource in the API token owner's account.
   contact: {}
-  version: ""
+  version:
+      $ref: components/version.yaml
 servers:
   - url: "https://api.apify.com"
     variables: {}