Update code.forgejo.org/forgejo/runner Docker tag to v7 (#704)

This PR contains the following updates:

| Package | Update | Change |
|---|---|---|
| [code.forgejo.org/forgejo/runner](https://forgejo.org) ([source](https://code.forgejo.org/forgejo/runner)) | major | `6.3.1` -> `7.0.0` |

---

### Release Notes

<details>
<summary>forgejo/runner (code.forgejo.org/forgejo/runner)</summary>

### [`v7.0.0`](https://code.forgejo.org/forgejo/runner/blob/HEAD/RELEASE-NOTES.md#700)

[Compare Source](https://code.forgejo.org/forgejo/runner/compare/v6.4.0...v7.0.0)

- Breaking change: [forgejo-runner exec --forgejo-instance replaces --gitea-instance](https://code.forgejo.org/forgejo/runner/pulls/652).
- [fix a v6.4.0 regression that fail a job when if: false](https://code.forgejo.org/forgejo/runner/issues/660).
- [forge.FORGEJO\_\* can be used instead of github.GITHUB\_\*](https://code.forgejo.org/forgejo/act/pulls/171), e.g. `forge.FORGEJO_REPOSITORY` is the same as `github.GITHUB_REPOSITORY`. The `GITHUB_*` environment variables are preserved indefinitely for backward compatibiliy with existing workflows and actions.
- [support for forgejo-runner exec --var](https://code.forgejo.org/forgejo/runner/pulls/645).
- [do not force WORKING\_DIR in service containers](https://code.forgejo.org/forgejo/runner/issues/304).
- [remove the local action cache if the remote has changed](https://code.forgejo.org/forgejo/act/pulls/142), e.g. when [DEFAULT\_ACTIONS\_URL](https://forgejo.org/docs/next/admin/config-cheat-sheet/#actions-actions) is modified in the forgejo configuration.

### [`v6.4.0`](https://code.forgejo.org/forgejo/runner/blob/HEAD/RELEASE-NOTES.md#640)

[Compare Source](https://code.forgejo.org/forgejo/runner/compare/v6.3.1...v6.4.0)

**Do not use, it [contains a regression](https://code.forgejo.org/forgejo/runner/issues/660) fixed in 7.0.0.**

- [Update code.forgejo.org/forgejo/act](https://code.forgejo.org/forgejo/runner/pulls/571) to v1.26.0. This brings [several security updates](https://code.forgejo.org/forgejo/act/compare/v1.25.1...v1.26.0), as well as [offline action caching](613090ecd7).
- [Remove unused x-runner-version header](https://code.forgejo.org/forgejo/runner/pulls/496).
- [Upgrade lxc-systemd using a URL instead of a version](https://code.forgejo.org/forgejo/runner/pulls/520).
- [Correctly use HTTP proxy if insecure is true](https://code.forgejo.org/forgejo/runner/pulls/535).
- [Update golang.org/x/crypto](https://code.forgejo.org/forgejo/runner/pulls/562) to a version that is not susceptible to DOS attack.
- [Update golang.org/x/net](https://code.forgejo.org/forgejo/runner/pulls/563) to a version with several security fixes.

</details>

---

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Reviewed-on: https://code.forgejo.org/forgejo/runner/pulls/704
Reviewed-by: earl-warren <earl-warren@noreply.code.forgejo.org>
Co-authored-by: Renovate Bot <bot@kriese.eu>
Co-committed-by: Renovate Bot <bot@kriese.eu>

examples/docker-compose/compose-forgejo-and-runner.yml

@@ -51,7 +51,7 @@ services:
       - 8080:3000
 
   runner-register:
-    image: code.forgejo.org/forgejo/runner:6.3.1
+    image: code.forgejo.org/forgejo/runner:7.0.0
     links:
       - docker-in-docker
       - forgejo
@@ -77,7 +77,7 @@ services:
       '
 
   runner-daemon:
-    image: code.forgejo.org/forgejo/runner:6.3.1
+    image: code.forgejo.org/forgejo/runner:7.0.0
     links:
       - docker-in-docker
       - forgejo