chore(deps): update docker.io/earthly/earthly docker tag to v0.8.4

This MR contains the following updates:

Package	Type	Update	Change
docker.io/earthly/earthly	image	patch	v0.8.3 -> v0.8.4

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images/.utils/gitlab-earthly.yaml

 .earthly:
-  image: docker.io/earthly/earthly:v0.8.3@sha256:6d464d12142616768bc86f7dc6aaa8237fb7e5b960934d42a1937f0b1caddab2
+  image: docker.io/earthly/earthly:v0.8.4@sha256:32e08fabd79f39bd58a76250c8801f6879540404bfea89eeb548414672fb607b
   variables:
     DOCKER_HOST: tcp://docker:2375
     FORCE_COLOR: 1