Update earthly/earthly digest to 22b8e7c (#35)

[![Mend
Renovate](https://app.renovatebot.com/images/banner.svg)](https://renovatebot.com)

This PR contains the following updates:

| Package | Update | Change |
|---|---|---|
| earthly/earthly | digest | `ec7ba23` -> `22b8e7c` |

---

### Configuration

📅 **Schedule**: Branch creation - "after 6am on monday" (UTC), Automerge
- At any time (no schedule defined).

🚦 **Automerge**: Enabled.

♻ **Rebasing**: Whenever PR becomes conflicted, or you tick the
rebase/retry checkbox.

🔕 **Ignore**: Close this PR and you won't be reminded about this update
again.

---

- [ ] <!-- rebase-check -->If you want to rebase/retry this PR, check
this box

---

This PR has been generated by [Mend
Renovate](https://www.mend.io/free-developer-tools/renovate/). View
repository job log
[here](https://developer.mend.io/github/earthly/dind).

<!--renovate-debug:eyJjcmVhdGVkSW5WZXIiOiIzNy4zMTMuMSIsInVwZGF0ZWRJblZlciI6IjM3LjMxMy4xIiwidGFyZ2V0QnJhbmNoIjoibWFpbiIsImxhYmVscyI6WyJyZW5vdmF0ZSJdfQ==-->

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

.arg

@@ -1,3 +1,3 @@
 DOCKERHUB_USER=earthly
 IMAGE_NAME=dind
-EARTHLY_REPO_VERSION=ec7ba239e925fa7336080b4c9dd4a2d708010b09
+EARTHLY_REPO_VERSION=22b8e7c901b2b3b8c6a7ba403b8fd8dd7f61277a