Update earthly/earthly digest to 0b28ef8 (#111)

This PR contains the following updates:

| Package | Update | Change |
|---|---|---|
| earthly/earthly | digest | `08b0d1f` -> `0b28ef8` |

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.arg

@@ -1,3 +1,3 @@
 DOCKERHUB_USER=earthly
 IMAGE_NAME=dind
-EARTHLY_REPO_VERSION=08b0d1ff1388b34d10ebb6a0164a7784cfbe9db2
+EARTHLY_REPO_VERSION=0b28ef80785fd88df1ec7e674475b02e046d5b36